Polynucleotides encoding cyclohexanone monooxygenases

ABSTRACT

The present invention relates to non-naturally occurring polypeptides useful for preparing armodafinil, polynucleotides encoding the polypeptides, and methods of using the polypeptides. The non-naturally occurring polypeptides of the present invention are effective in carrying out biocatalytic conversion of the (i) 2-(benzhydrylsulfinyl)acetamide to (−)-2-[(R)-(diphenylmethyl)sulfinyl]acetamide (armodafinil), or (ii) benzhydryl-thioacetic acid to (R)-2-(benzhydrylsulfinyl)acetic acid, which is a pivotal intermediate in the synthesis of armodafinil, in enantiomeric excess.

The present application is a Continuation of co-pending U.S. patentapplication Ser. No. 16/113,684, filed Aug. 27, 2018, now U.S. Pat. No.10,400,223 which is a Continuation of co-pending U.S. patent applicationSer. No. 15/903,264, filed Feb. 23, 2018, now U.S. Pat. No. 10,087,426,which is a Continuation of U.S. patent application Ser. No. 15/698,319,filed Sep. 7, 2017, now U.S. Pat. No. 9,938,509, which is a Continuationof U.S. patent application Ser. No. 15/352,970, filed Nov. 16, 2016, nowU.S. Pat. No. 9,765,306, which is a Continuation of U.S. patentapplication Ser. No. 15/159,578, filed May 19, 2016, now U.S. Pat. No.9,528,095, which is a Continuation of U.S. patent application Ser. No.14/997,277, filed Jan. 15, 2016, now U.S. Pat. No. 9,365,835, which is aDivisional of Ser. No. 13/992,138, filed Jun. 6, 2013, now U.S. Pat. No.9,267,159, which claims priority to PCT/US2011/063809, filed Dec. 7,2011, which claims priority to U.S. Prov. Pat. Appln. Ser. No.61/421,123, filed Dec. 8, 2010, all of which are incorporated herein byreference, in their entireties and for all purposes.

TECHNICAL FIELD

This disclosure relates to biocatalysts and processes using thebiocatalysts for the preparation of armodafinil.

REFERENCE TO SEQUENCE LISTING, TABLE OR COMPUTER PROGRAM

The Sequence Listing is concurrently submitted herewith with thespecification as an ASCII formatted text file via EFS-Web with a filename of CX2-050USP1_ST25.txt with a creation date of Dec. 8, 2010, and asize of 510551 bytes. The Sequence Listing filed via EFS-Web is part ofthe specification and is hereby incorporated in its entirety byreference herein.

BACKGROUND

Armodafinil (Nuvigil) is the active (−)-(R)-enantiomer of the racemicdrug modafinil (Provigil). Armodafinil, whose structure is shown hereinas compound (2a), also has the chemical name(−)-2-[(R)-(diphenylmethyl)sulfinyl]acetamide.

Armodafinil is a stimulant-like drug approved by the FDA for thetreatment of narcolepsy and shift work sleep disorder, and as anadjunctive treatment for obstructive sleep apnea. It is also beingevaluated as a treatment for other medical conditions such as bipolardepression, cognition abnormalities associated with schizophrenia, andfatigue in conditions such as Parkinson's disease and cancer.

The chemical process for preparing armodafinil involves either KaganSharpless-type oxidation (Ti(isopropoxide)₄/tartrate) of2-(benzhydrysulfinyl)acetamide (see e.g., PCT Publ. No. WO2005/028428)or classic resolution of racemic modafinil acid by(R)-naphthylethylamine (see e.g., PCT Publ. No. WO2007/103221).

A biocatalytic route for the synthesis of armodafinil could providesignificant advantages over above chemical processes if capable of highefficiency (e.g., high substrate loadings) and high enantioselectivity.An enzymatic oxidation has been described using a phenylacetonemonooxygenase in a step for converting 2-benzhydrylthioacetic acid to2-(benzhydrylsulfinyl)acetic acid (see e.g., US Publ. No.US2007/087422A1). Also, microbial oxidations of benzhydrylsulfanylacetic acid or benzhydrylsulfanyl acetamide have been described thatprovide mixtures of (S)-modafinil and (R)-modafinil (see e.g., Olivo etal., “Microbial oxidation/amidation of benzhydrylsulfanyl acetic acid.Synthesis of (+)-modafinil,” Tetrahedron Asymmetry (2005), 16(21),3507-3511; PCT publ. no. WO2007/027328A2). Both processes, however,provide poor enantioselectivity and poor yield of product.

Cyclohexanone monooxygenases (CHMO) were originally identified for theirability to carry out the conversion of cyclohexanone to ε-caprolactone,a seven membered cyclic product. The CHMO biocatalytic reaction uses O₂and a co-factor NAPDH to generate the caprolactone, oxidized cofactorNADP+, and H₂O. CHMOs are flavin dependent enzymes and contain a flavinprosthetic group, generally flavin adenine dinucleotide (FAD). This FADprosthetic group is bound to the enzyme and is believed to participatein the catalytic reaction by forming a peroxyflavin intermediate (see,e.g., Sheng et al., 2001, Biochemistry 40(37):11156-67; Malito et al.,2004, Proc Natl Acad Sci USA 101(36):13157-13162). CHMOs have also beenused as biocatalysts for the enantioselective air-oxidation of prochiralthioethers to form chiral sulfoxides (see, e.g., Light et al., 1982,“Studies on the chirality of sulfoxidation catalyzed by bacterialflavoenzyme cyclohexanone monooxygenase and hog liver flavin adeninedinucleotide containing monooxygenase,” Biochemistry, 21(10):2490-8; andReetz et al., 2004, Angew. Chem. Int. Ed. 43:4078-4081). CHMOs alsorecognize a variety of aryl-alkyl sulfide substrates (see e.g., Pasta etal., 1995, Tetrahedron: Asymmetry 6(4):933-936; Yeung and Rettie, 2005,“Prochiral Sulfoxidation as a probe for Flavin-ContainingMonooxygenases,” in Methods in Molecular Biology: Cytochrome P450Protocols 320:163-172; Colonna et al., 2000, Chirality 13(1):40-42; andAlphand et al., 2003, Trends Biotechnology 21(7):318-323). The wild-typeCHMO from Acinetobacter sp. NCIMB9871 has been shown to catalyze thesulfoxidation of 4-tolyl-sulfide but the resulting product ispredominantly the (S)-sulfoxide (S:R˜86:13) (see e.g., Light, et al.1982 supra).

There is a need for improved enzymes capable of being used in abiocatalytic process for preparing armodafinil. Particularly desirablewould be CHMOs capable of increased activity in large scale processeshaving high substrate loadings, high percent conversion, and capable ofyielding armodafinil as product in high purity and enantiomeric excess.

SUMMARY

The present disclosure is directed to non-naturally occurringpolypeptides having cyclohexanone monooxygenase (CHMO) activity,polynucleotides encoding the polypeptides, methods of the making thepolypeptides, and methods of using the polypeptides in biocatalyticprocesses for the preparation of armodafinil. Specifically, thedisclosure processes for the preparation of armodafinil including eitherof the following two biocatalytic reactions: (i) conversion of the amidesubstrate 2-(benzhydrylsulfinyl)acetamide (compound (1a)) to the productarmodafinil, (−)-2-[(R)-(diphenylmethyl)sulfinyl]acetamide (compound(2a)); or (ii) conversion of the acid substrate, benzhydryl-thioaceticacid (compound (1b)) (also referred to as BHTA) to(R)-2-(benzhydrylsulfinyl)acetic acid (compound (2b)) (also referred toas (R)-BHSO or (R)-modafinic acid), which is an acid intermediate easilyconverted to the amide product, armodafinil in enantiomeric excess.

While naturally occurring polypeptides having CHMO activity do notefficiently convert compound (1a) to compound (2a), or compound (1b) tocompound (2b), in some embodiments, the non-naturally occurring (orengineered) polypeptides having CHMO activity of the present disclosureare capable of carrying out these conversions with improved propertiesincluding, high enantiomeric excess (e.g., at least about 90% e.e.),increased activity (e.g., at least about 10-fold increased activityrelative to the reference wild-type polypeptide SEQ ID NO: 2), highpercent conversion (e.g., at least about 90% conversion in 24 h), in thepresence of high substrate loadings (e.g., at least about 5 g/L ofsubstrate). In some embodiments, the present disclosure provides anon-naturally occurring polypeptide having CHMO activity capable ofconverting compound (1a) to compound (2a), and/or compound (1b) tocompound (2b), with at least 2-fold, at least 10-fold, at least 25-fold,at least 40-fold, or at least 60-fold increased specific enzyme activityrelative to the specific enzyme activity of the polypeptide of SEQ IDNO: 2.

In some embodiments the present disclosure provides a non-naturallyoccurring polypeptide having CHMO activity wherein the amino acidsequence of the polypeptide has at least 80%, 85%, 86%, 87%, 88%, 89%,90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity toSEQ ID NO: 2 and includes one or more amino acid differences relative toSEQ ID NO: 2 selected from the following: X143C, E, F, G, H, K, M, P, Q,S, T, or W; X246A, E, G, I, L, N, P, S, T, or V; X277C, D, E, G, H, L,M, P, S, T, V, or W; X278A, C, G, H, K, N, Q, S, T, or V; X280L, T, orW; X281A, C, H, K, L, M, N, R, T, V, W, or Y; X326A, D, E, F, G, H, L,M, N, P, R, V, or W; X426G, Q, or T; X432E, I, K, N, Q, T, V, or W;X433S; X435G, K, V, or Y; X490A, C, D, E, G, I, L, M, N, S, or Y; andX532M. In some embodiments, the polypeptide is capable of converting theacid substrate compound (1b) to compound (2b), and/or the polypeptide iscapable of converting the acid substrate of compound (1b) to theR-enantiomer compound (2b) in at least 50% ee.

In some embodiments of the non-naturally occurring polypeptide havingCHMO activity, the polypeptide amino acid sequence can comprise one ormore amino acid differences relative to SEQ ID NO: 2 selected from:X143G; X278G; X326R; and X490L. Further, in some embodiments, the aminoacid sequence can comprise at least the following amino acid differencesrelative to SEQ ID NO: 2: X277I; X278A, or G; X280T or Y; X281I; X326R;and X490L or X490Q. In additional embodiments, the polypeptide aminoacid sequence may further comprise at least one combination of aminoacid differences relative to SEQ ID NO: 2 selected from the exemplaryCHMO polypeptides disclosed herein.

The present disclosure also provides non-naturally occurringpolypeptides having CHMO activity comprising an amino acid sequencewhich have at least 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%,94%, 95%, 96%, 97%, 98%, or 99% sequence identity to any one of SEQ IDNO: 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38,40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74,76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108,110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 132, 134, 136,138, 140, or 142. In some embodiments, said non-naturally occurringpolypeptide having CHMO activity further have at least 10-fold increasein specific enzyme activity in comparison with SEQ ID NO: 2 and at least75% enantiomeric excess in converting compound (1a) to compound (2a),and/or compound (1b) to compound (2b).

In another aspect, provided herein are polynucleotides encoding themonooxygenase polypeptides, expression vectors comprising thepolynucleotides, and host cells capable of expressing the polypeptides.Accordingly, in some embodiments, the present disclosure also providesmethods of manufacturing the non-naturally occurring CHMO polypeptidescapable of converting compound (1a) to compound (2a) and/or compound(1b) to compound (2b), wherein the methods comprise culturing a hostcell capable of expressing a polynucleotide encoding the engineeredtransaminase polypeptide and isolating the polypeptide from the hostcell. Exemplary polynucleotide sequences are provided in the sequencelisting incorporated by reference herein and include SEQ ID NO: 3, 5, 7,9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43,45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79,81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111,113, 115, 117, 119, 121, 123, 125, 127, 129, 131, 133, 135, 137, 139, or141.

The present disclosure is also directed to a method for preparingcompound (2a) from compound (1a) in enantiomeric excess, the methodcomprising contacting compound (1a) with a non-naturally occurringpolypeptide having CHMO activity of the present disclosure in thepresence of cofactor NADPH or NADH under suitable reaction conditions.Similarly, the present disclosure also provides a method for preparingcompound (2b) from compound (1b) in enantiomeric excess, the methodcomprising contacting compound (1b) with a non-naturally occurring CHMOpolypeptide of the present disclosure in the presence of cofactor NADPHor NADH under suitable reaction conditions. Suitable reaction conditionscan include a source of molecular oxygen O₂, a cofactor recycling system(e.g., a KRED enzyme and a secondary alcohol), and a co-solvent (e.g.,2-7.5% NMP, or 5-15% PEG200).

Further, the present disclosure is also directed to a method forpreparing compound (2a) from compound (1b) in enantiomeric excess. Themethod comprises the steps of: (a) preparing compound (2b) from compound(1b) with a non-naturally occurring polypeptide having CHMO activity ofthe present disclosure in the presence of cofactor NADPH or NADH undersuitable reaction conditions, and (b) preparing compound (2a) fromcompound (2b) by esterification and amidation.

DETAILED DESCRIPTION 1.1 Definitions

The technical and scientific terms used in the descriptions herein willhave the meanings commonly understood by one of ordinary skill in theart, unless specifically defined otherwise. Accordingly, the followingterms are intended to have the following meanings.

“Protein”, “polypeptide,” and “peptide” are used interchangeably hereinto denote a polymer of at least two amino acids covalently linked by anamide bond, regardless of length or post-translational modification(e.g., glycosylation, phosphorylation, lipidation, myristilation,ubiquitination, etc.). Included within this definition are D- andL-amino acids, and mixtures of D- and L-amino acids.

“Coding sequence” refers to that portion of a nucleic acid (e.g., agene) that encodes an amino acid sequence of a protein.

“Naturally occurring” or “wild-type” refers to the form found in nature.For example, a naturally occurring or wild-type polypeptide orpolynucleotide sequence is a sequence present in an organism that can beisolated from a source in nature and which has not been intentionallymodified by human manipulation.

“Non-naturally occurring” or “engineered” or “recombinant” when used inthe present disclosure with reference to, e.g., a cell, nucleic acid, orpolypeptide, refers to a material, or a material corresponding to thenatural or native form of the material, that has been modified in amanner that would not otherwise exist in nature, or is identical theretobut produced or derived from synthetic materials and/or by manipulationusing recombinant techniques. Non-limiting examples include, amongothers, recombinant cells expressing genes that are not found within thenative (non-recombinant) form of the cell or express native genes thatare otherwise expressed at a different level.

“Percentage of sequence identity” and “percentage homology” are usedinterchangeably herein to refer to comparisons among polynucleotides andpolypeptides, and are determined by comparing two optimally alignedsequences over a comparison window, wherein the portion of thepolynucleotide or polypeptide sequence in the comparison window maycomprise additions or deletions (i.e., gaps) as compared to thereference sequence for optimal alignment of the two sequences. Thepercentage may be calculated by determining the number of positions atwhich the identical nucleic acid base or amino acid residue occurs inboth sequences to yield the number of matched positions, dividing thenumber of matched positions by the total number of positions in thewindow of comparison and multiplying the result by 100 to yield thepercentage of sequence identity. Alternatively, the percentage may becalculated by determining the number of positions at which either theidentical nucleic acid base or amino acid residue occurs in bothsequences or a nucleic acid base or amino acid residue is aligned with agap to yield the number of matched positions, dividing the number ofmatched positions by the total number of positions in the window ofcomparison and multiplying the result by 100 to yield the percentage ofsequence identity. Those of skill in the art appreciate that there aremany established algorithms available to align two sequences. Optimalalignment of sequences for comparison can be conducted, e.g., by thelocal homology algorithm of Smith and Waterman, 1981, Adv. Appl. Math.2:482, by the homology alignment algorithm of Needleman and Wunsch,1970, J. Mol. Biol. 48:443, by the search for similarity method ofPearson and Lipman, 1988, Proc. Natl. Acad. Sci. USA 85:2444, bycomputerized implementations of these algorithms (GAP, BESTFIT, FASTA,and TFASTA in the GCG Wisconsin Software Package), or by visualinspection (see generally, Current Protocols in Molecular Biology, F. M.Ausubel et al., eds., Current Protocols, a joint venture between GreenePublishing Associates, Inc. and John Wiley & Sons, Inc., (1995Supplement) (Ausubel)). Examples of algorithms that are suitable fordetermining percent sequence identity and sequence similarity are theBLAST and BLAST 2.0 algorithms, which are described in Altschul et al.,1990, J. Mol. Biol. 215: 403-410 and Altschul et al., 1977, NucleicAcids Res. 3389-3402, respectively. Software for performing BLASTanalyses is publicly available through the National Center forBiotechnology Information website. This algorithm involves firstidentifying high scoring sequence pairs (HSPs) by identifying shortwords of length W in the query sequence, which either match or satisfysome positive-valued threshold score T when aligned with a word of thesame length in a database sequence. T is referred to as, theneighborhood word score threshold (Altschul et al, supra). These initialneighborhood word hits act as seeds for initiating searches to findlonger HSPs containing them. The word hits are then extended in bothdirections along each sequence for as far as the cumulative alignmentscore can be increased. Cumulative scores are calculated using, fornucleotide sequences, the parameters M (reward score for a pair ofmatching residues; always >0) and N (penalty score for mismatchingresidues; always <0). For amino acid sequences, a scoring matrix is usedto calculate the cumulative score. Extension of the word hits in eachdirection are halted when: the cumulative alignment score falls off bythe quantity X from its maximum achieved value; the cumulative scoregoes to zero or below, due to the accumulation of one or morenegative-scoring residue alignments; or the end of either sequence isreached. The BLAST algorithm parameters W, T, and X determine thesensitivity and speed of the alignment. The BLASTN program (fornucleotide sequences) uses as defaults a wordlength (W) of 11, anexpectation (E) of 10, M=5, N=−4, and a comparison of both strands. Foramino acid sequences, the BLASTP program uses as defaults a wordlength(W) of 3, an expectation (E) of 10, and the BLOSUM62 scoring matrix (seeHenikoff and Henikoff, 1989, Proc Natl Acad Sci USA 89:10915). Exemplarydetermination of sequence alignment and % sequence identity can employthe BESTFIT or GAP programs in the GCG Wisconsin Software package(Accelrys, Madison Wis.), using default parameters provided.

“Reference sequence” refers to a defined sequence used as a basis for asequence comparison. A reference sequence may be a subset of a largersequence, for example, a segment of a full-length gene or polypeptidesequence. Generally, a reference sequence is at least 20 nucleotide oramino acid residues in length, at least 25 residues in length, at least50 residues in length, or the full length of the nucleic acid orpolypeptide. Since two polynucleotides or polypeptides may each (1)comprise a sequence (i.e., a portion of the complete sequence) that issimilar between the two sequences, and (2) may further comprise asequence that is divergent between the two sequences, sequencecomparisons between two (or more) polynucleotides or polypeptide aretypically performed by comparing sequences of the two polynucleotides orpolypeptides over a “comparison window” to identify and compare localregions of sequence similarity. In some embodiments, a “referencesequence” can be based on a primary amino acid sequence, where thereference sequence is a sequence that can have one or more changes inthe primary sequence. For instance, a “reference sequence based on SEQID NO:2 having at the residue corresponding to X9 a threonine” refers toa reference sequence in which the corresponding residue at X9 in SEQ IDNO:2, which is a alanine, has been changed to threonine.

“Comparison window” refers to a conceptual segment of at least about 20contiguous nucleotide positions or amino acids residues wherein asequence may be compared to a reference sequence of at least 20contiguous nucleotides or amino acids and wherein the portion of thesequence in the comparison window may comprise additions or deletions(i.e., gaps) of 20 percent or less as compared to the reference sequence(which does not comprise additions or deletions) for optimal alignmentof the two sequences. The comparison window can be longer than 20contiguous residues, and includes, optionally 30, 40, 50, 100, or longerwindows.

“Corresponding to”, “reference to” or “relative to” when used in thecontext of the numbering of a given amino acid or polynucleotidesequence refers to the numbering of the residues of a specifiedreference sequence when the given amino acid or polynucleotide sequenceis compared to the reference sequence. In other words, the residuenumber or residue position of a given polymer is designated with respectto the reference sequence rather than by the actual numerical positionof the residue within the given amino acid or polynucleotide sequence.For example, a given amino acid sequence, such as that of an engineeredcyclohexanone monooxygenase, can be aligned to a reference sequence byintroducing gaps to optimize residue matches between the two sequences.In these cases, although the gaps are present, the numbering of theresidue in the given amino acid or polynucleotide sequence is made withrespect to the reference sequence to which it has been aligned.

“Amino acid difference” or “residue difference” refers to a change inthe amino acid residue at a position of a polypeptide sequence relativeto the amino acid residue at a corresponding position in a referencesequence. The positions of amino acid differences generally are referredto herein as “Xn,” where n refers to the corresponding position in thereference sequence upon which the residue difference is based. Forexample, a “residue difference at position X3 as compared to SEQ ID NO:2” refers to a change of the amino acid residue at the polypeptideposition corresponding to position 3 of SEQ ID NO:2. Thus, if thereference polypeptide of SEQ ID NO: 2 has a glutamine at position 3,then a “residue difference at position X3 as compared to SEQ ID NO:2” anamino acid substitution of any residue other than glutamine at theposition of the polypeptide corresponding to position 3 of SEQ ID NO: 2.In most instances herein, the specific amino acid residue difference ata position is indicated as “XnY” where “Xn” specified the correspondingposition as described above, and “Y” is the single letter identifier ofthe amino acid found in the engineered polypeptide (i.e., the differentresidue than in the reference polypeptide). In some instances (e.g., inTables 2A, 2B, and 2C), the present disclosure also provides specificamino acid differences denoted by the conventional notation “AnB”, whereA is the single letter identifier of the residue in the referencesequence, “n” is the number of the residue position in the referencesequence, and B is the single letter identifier of the residuesubstitution in the sequence of the engineered polypeptide. In someinstances, a polypeptide of the present disclosure can include one ormore amino acid residue differences relative to a reference sequence,which is indicated by a list of the specified positions where changesare made relative to the reference sequence. The present disclosureincludes engineered polypeptide sequences comprising one or more aminoacid differences that include either/or both conservative andnon-conservative amino acid substitutions.

“Conservative amino acid substitution” refers to a substitution of aresidue with a different residue having a similar side chain, and thustypically involves substitution of the amino acid in the polypeptidewith amino acids within the same or similar defined class of aminoacids. By way of example and not limitation, an amino acid with analiphatic side chain may be substituted with another aliphatic aminoacid, e.g., alanine, valine, leucine, and isoleucine; an amino acid withhydroxyl side chain is substituted with another amino acid with ahydroxyl side chain, e.g., serine and threonine; an amino acids havingaromatic side chains is substituted with another amino acid having anaromatic side chain, e.g., phenylalanine, tyrosine, tryptophan, andhistidine; an amino acid with a basic side chain is substituted withanother amino acid with a basis side chain, e.g., lysine and arginine;an amino acid with an acidic side chain is substituted with anotheramino acid with an acidic side chain, e.g., aspartic acid or glutamicacid; and a hydrophobic or hydrophilic amino acid is replaced withanother hydrophobic or hydrophilic amino acid, respectively. Exemplaryconservative substitutions are provided in Table 1 below:

TABLE 1 Residue Possible Conservative Substitutions A, L, V, I Otheraliphatic (A, L, V, I) Other non-polar (A, L, V, I, G, M) G, M Othernon-polar (A, L, V, I, G, M) D, E Other acidic (D, E) K, R Other basic(K, R) N, Q, S, T Other polar H, Y, W, F Other aromatic (H, Y, W, F) C,P None

“Non-conservative substitution” refers to substitution of an amino acidin the polypeptide with an amino acid with significantly differing sidechain properties. Non-conservative substitutions may use amino acidsbetween, rather than within, the defined groups and affects (a) thestructure of the peptide backbone in the area of the substitution (e.g.,proline for glycine) (b) the charge or hydrophobicity, or (c) the bulkof the side chain. By way of example and not limitation, an exemplarynon-conservative substitution can be an acidic amino acid substitutedwith a basic or aliphatic amino acid; an aromatic amino acid substitutedwith a small amino acid; and a hydrophilic amino acid substituted with ahydrophobic amino acid.

“Deletion” refers to modification to the polypeptide by removal of oneor more amino acids from the reference polypeptide. Deletions cancomprise removal of 1 or more amino acids, 2 or more amino acids, 5 ormore amino acids, 10 or more amino acids, 15 or more amino acids, or 20or more amino acids, up to 10% of the total number of amino acids, or upto 20% of the total number of amino acids making up the reference enzymewhile retaining enzymatic activity and/or retaining the improvedproperties of an engineered CHMO enzyme. Deletions can be directed tothe internal portions and/or terminal portions of the polypeptide. Invarious embodiments, the deletion can comprise a continuous segment orcan be discontinuous.

“Insertion” refers to modification to the polypeptide by addition of oneor more amino acids from the reference polypeptide. In some embodiments,the improved engineered CHMO enzymes comprise insertions of one or moreamino acids to the naturally occurring CHMO polypeptide as well asinsertions of one or more amino acids to other improved CHMOpolypeptides. Insertions can be in the internal portions of thepolypeptide, or to the carboxy or amino terminus. Insertions as usedherein include fusion proteins as is known in the art. The insertion canbe a contiguous segment of amino acids or separated by one or more ofthe amino acids in the naturally occurring polypeptide.

“Fragment” as used herein refers to a polypeptide that has anamino-terminal and/or carboxy-terminal deletion, but where the remainingamino acid sequence is identical to the corresponding positions in thesequence. Fragments can be at least 14 amino acids long, at least 20amino acids long, at least 50 amino acids long or longer, and up to 70%,80%, 90%, 95%, 98%, and 99% of a full-length polypeptide.

“Improved enzyme property” refers to a functional property of apolypeptide that can be measured under suitable conditions and whichexhibits improvement as compared to the same property of a referencepolypeptide. For the engineered CHMO polypeptides described herein, thecomparison is generally made to the wild-type CHMO enzyme, although insome embodiments, the reference polypeptide can be another improvedengineered CHMO polypeptide. Enzyme properties for which improvement isdesirable include, but are not limited to, enzymatic activity (which canbe expressed in terms of percent conversion of the substrate), thermostability, solvent stability, pH activity profile, cofactorrequirements, refractoriness to inhibitors (e.g., substrate or productinhibition), stereospecificity, and stereoselectivity (includingenantioselectivity).

“Suitable reaction conditions” refers to those conditions in thebiocatalytic reaction solution (e.g., ranges of enzyme loading,substrate loading, cofactor loading, T, pH, buffers, co-solvents, etc.)under which a non-naturally occurring CHMO polypeptide of the presentdisclosure is capable of converting compound (1a) to compound (2a), orcompound (1b) to compound (2b). Exemplary “suitable reaction conditions”are provided in the present disclosure and illustrated by the Examples.

“Increased enzymatic activity” or “increased activity” refers to animproved property of an engineered enzyme, which can be represented byan increase in enzyme activity (e.g., product produced/time/weightprotein) or an increase in percent conversion of the substrate to theproduct (e.g., percent conversion of starting amount of substrate toproduct in a specified time period using a specified amount ofcyclohexanone monooxygenase) as compared to a reference enzyme.Exemplary methods to determine enzyme activity are provided in theExamples. Any property relating to enzyme activity may be affected,including the classical enzyme properties of K_(m), V_(max) or k_(cat),changes of which can lead to increased enzymatic activity. TheCyclohexanone monooxygenase activity can be measured by any one ofstandard assays used for measuring cyclohexanone monooxygenases, such aschange in substrate or product concentration, or change in concentrationof the cofactor (in absence of a cofactor regenerating system).Comparisons of enzyme activities are made using a defined preparation ofenzyme, a defined assay under a set condition, and one or more definedsubstrates, as further described in detail herein. Generally, whenenzymes in cell lysates are compared, the numbers of cells and theamount of protein assayed are determined as well as use of identicalexpression systems and identical host cells to minimize variations inamount of enzyme produced by the host cells and present in the lysates.

“Conversion” refers to the enzymatic transformation of a substrate tothe corresponding product. “Percent conversion” refers to the percent ofthe substrate that is converted to the product within a period of timeunder specified conditions. Thus, for example, the “enzymatic activity”or “activity” of a CHMO polypeptide can be expressed as “percentconversion” of the substrate to the product.

“Stereoselectivity” refers to the preferential formation in a chemicalor enzymatic reaction of one stereoisomer over another.Stereoselectivity can be partial, where the formation of onestereoisomer is favored over the other, or it may be complete where onlyone stereoisomer is formed. When the stereoisomers are enantiomers, thestereoselectivity is referred to as enantioselectivity, the fraction(typically reported as a percentage) of one enantiomer in the sum ofboth. It is commonly alternatively reported in the art (typically as apercentage) as the enantiomeric excess (e.e.) calculated therefromaccording to the formula [major enantiomer−minor enantiomer]/[majorenantiomer+minor enantiomer]. Where the stereoisomers arediastereoisomers, the stereoselectivity is referred to asdiastereoselectivity, the fraction (typically reported as a percentage)of one diastereomer in a mixture of two diastereomers, commonlyalternatively reported as the diastereomeric excess (d.e.). Enantiomericexcess and diastereomeric excess are types of stereomeric excess.“Highly stereoselective” refers to a chemical or enzymatic reaction thatis capable of converting (i) a substrate 2-(benzhydrylsulfinyl)acetamide(compound (1a)) to (−)-2-[(R)-(diphenylmethyl)sulfinyl]acetamide(compound (2a), armodafinil), or (ii) a substrate benzhydryl-thioaceticacid (compound (1b)) to (R)-2-(benzhydrylsulfinyl)acetic acid (compound(2b), (R)-modafinic acid); with at least about 85% stereoisomericexcess.

“Thermostable” or “thermal stable” are used interchangeably to refer toa polypeptide that is resistant to inactivation when exposed to a set oftemperature conditions (e.g., 40-80° C.) for a period of time (e.g.,0.5-24 hrs) compared to the untreated enzyme, thus retaining a certainlevel of residual activity (e.g., more than 60% to 80% for example)after exposure to elevated temperatures.

“Isolated polypeptide” refers to a polypeptide which is substantiallyseparated from other contaminants that naturally accompany it, e.g.,protein, lipids, and polynucleotides. The term embraces polypeptideswhich have been removed or purified from their naturally-occurringenvironment or expression system (e.g., host cell or in vitrosynthesis). The improved CHMO enzymes may be present within a cell,present in the cellular medium, or prepared in various forms, such aslysates or isolated preparations. As such, in some embodiments, theengineered CHMO polypeptides of the present disclosure can be anisolated polypeptide.

“Substantially pure polypeptide” refers to a composition in which thepolypeptide species is the predominant species present (i.e., on a molaror weight basis it is more abundant than any other individualmacromolecular species in the composition), and is generally asubstantially purified composition when the object species comprises atleast about 50 percent of the macromolecular species present by mole or% weight. Generally, a substantially pure engineered CHMO polypeptidecomposition will comprise about 60% or more, about 70% or more, about80% or more, about 90% or more, about 95% or more, and about 98% or moreof all macromolecular species by mole or % weight present in thecomposition. Solvent species, small molecules (<500 Daltons), andelemental ion species are not considered macromolecular species. In someembodiments, the isolated improved CHMO polypeptide is a substantiallypure polypeptide composition.

“Heterologous” polynucleotide refers to any polynucleotide that isintroduced into a host cell by laboratory techniques, and includespolynucleotides that are removed from a host cell, subjected tolaboratory manipulation, and then reintroduced into a host cell.

“Codon optimized” refers to changes in the codons of the polynucleotideencoding a protein to those preferentially used in a particular organismsuch that the encoded protein is efficiently expressed in the organismof interest. In some embodiments, the polynucleotides encoding the CHMOenzymes may be codon optimized for optimal production from the hostorganism selected for expression.

“Control sequence” is defined herein to include all components, whichare necessary or advantageous for the expression of a polynucleotideand/or polypeptide of the present disclosure. Each control sequence maybe native or foreign to the polynucleotide of interest. Such controlsequences include, but are not limited to, a leader, polyadenylationsequence, propeptide sequence, promoter, signal peptide sequence, andtranscription terminator.

“Operably linked” is defined herein as a configuration in which acontrol sequence is appropriately placed (i.e., in a functionalrelationship) at a position relative to a polynucleotide of interestsuch that the control sequence directs or regulates the expression ofthe polynucleotide and/or polypeptide of interest.

“Cofactor regeneration system” refers to a set of reactants thatparticipate in a reaction that reduces the oxidized form of the cofactor(e.g., NADP+ to NADPH). Cofactors oxidized by the cyclohexanonemonooxygenase-catalyzed reduction of the substrate are regenerated inreduced form by the cofactor regeneration system. Cofactor regenerationsystems comprise a stoichiometric reductant that is a source of reducinghydrogen equivalents and is capable of reducing the oxidized form of thecofactor. The cofactor regeneration system may further comprise acatalyst, for example an enzyme catalyst that catalyzes the reduction ofthe oxidized form of the cofactor by the reductant. Cofactorregeneration systems to regenerate NADH or NADPH from NAD+ or NADP+,respectively, are known in the art and may be used in the methodsdescribed herein.

The term “glucose dehydrogenase” refers to an NAD⁺ or NADP⁺-dependentenzyme that catalyzes the conversion of D-glucose and NAD⁺ or NADP⁺ togluconic acid and NADH or NADPH, respectively.

The term “an alcohol dehydrogenase” is used herein to refer to an NAD⁺or NADP⁺-dependent enzyme that catalyzes the conversion of an alcohol(e.g., isopropanol) and NAD⁺ or NADP⁺ to a ketone and NADH or NADPH,respectively.

1.2 Non-Naturally Occurring or Engineered Cyclohexanone MonooxygenasePolypeptides

The present disclosure provides highly stereoselective and efficientnon-naturally occurring polypeptides having cyclohexanone monooxygenase(CHMO) activity. In some embodiments the non-naturally occurringpolypeptides having CHMO activity are capable of mediating thebiocatalytic conversion of: (i) 2-(benzhydrylsulfinyl)acetamide(compound (1a)) to (−)-2-[(R)-(diphenylmethyl)sulfinyl]acetamide(compound (2a)); or (ii) benzhydryl-thioacetic acid (compound (1b), or“BHTA”) to (R)-2-(benzhydrylsulfinyl)acetic acid (compound (2b), or“(R)-BHSO,” or “(R)-modafinic acid”).

A general biocatalytic scheme for using an engineered CHMO polypeptide(i.e., “CHMO variant”) of the present disclosure to convert the amidesubstrate of compound (1a) to the product of compound (2a) is shown inScheme 1:

Alternatively, the engineered CHMO polypeptides of the presentdisclosure can be used in a biocatalytic scheme to convert the acidsubstrate of compound (1b) to the product of compound (2b) as shown inScheme 2:

The acid substrate product of compound (2b) is an intermediate usefulfor the preparation of armodafinil (compound (2a)), in enantiomericexcess. The engineered polypeptides having CHMO activity describedherein have been designed by changing the amino acid sequence of anaturally occurring CHMO to form polypeptides with the desired enzymaticproperties, e.g., enzyme activity, stereoselectivity, by-productformation, thermostability, and expression. The following detaileddescription describes the CHMO polypeptides and processes for carryingout the conversion of either: (i) compound (1a) to compound (2a); or(ii) compound (1b) to compound (2b).

Naturally occurring polypeptides having CHMO activity do not efficientlyconvert compound (1a) to compound (2a), or compound (1b) to compound(2b). The engineered polypeptides having CHMO activity of the presentdisclosure have been designed starting from the cyclohexanonemonooxygenase of Acinetobacter sp. NCIMB9871. In contrast to thewild-type enzyme, these engineered CHMO polypeptides are capable ofcarrying out this conversion with improved properties including, highenantiomeric excess (e.g., at least about 75% e.e.), increased enzymeactivity (e.g., at least about 2-fold increased activity relative to thereference polypeptide SEQ ID NO: 2), high percent conversion (e.g., atleast about 80% conversion in 24 h), in the presence of high substrateloadings (e.g., at least about 10 g/L of substrate compound (1a) orcompound (2a)).

The non-naturally occurring polypeptides having CHMO activity of thepresent disclosure comprise amino acid sequences that have one or moreresidue differences as compared to the reference sequence of thewild-type Acinetobacter sp. NCIMB9871 CHMO polypeptide (SEQ ID NO: 2).The residue differences occur at residue positions that affect enzymeactivity, stereoselectivity, thermostability, expression, or variouscombinations thereof. In some embodiments, the residue differencesrelative to the wild-type sequence allow the engineered polypeptideshaving CHMO activity to convert the amide substrate compound (1a) tocompound (2a) and/or the acid substrate compound (1b) to compound (2b)with at least 2-fold, at least 10-fold, at least 25-fold, at least40-fold, or at least 60-fold increased activity relative to the activityof a reference polypeptide of SEQ ID NO: 2, 4, or 38. Further, theseengineered polypeptides are capable of highly stereoselective conversionof the amide substrate compound (1a) to compound (2a), and/or the acidsubstrate compound (1b) to compound (2b) in an enantiomeric excess(e.e.) of at least 75%, at least 80%, at least 85%, at least 90%, atleast 95%, at least 97%, at least 98%, at least 99%, at least 99.8%, ormore. Additionally, in some embodiments, the engineered polypeptideshaving CHMO activity of the present disclosure are capable of at leastabout 80%, or 85%, or 90% conversion of compound (1a) to compound (2a),or compound (1b) to compound (2b), in 24 hours with a substrate loadingof at least about 10 g/L, or 20 g/L, or 30 g/L, or 50 g/L, or 75 g/L, or100 g/L.

The biocatalytic conversions of Scheme 1 and Scheme 2 can be carried outusing whole cells expressing the engineered polypeptides having CHMOactivity, or purified or partially purified preparations of thepolypeptides (e.g., shake-flask powders, downstream processed powders,or other fermentation powders). For in vitro applications, a cofactor(NADH or NADPH) and a cofactor regenerating system such as ketoreductase(KRED) along with a secondary substrate such as isopropyl alcohol (IPA)at e.g., 5% (v/v) concentration can be used in conjunction with theengineered CHMO polypeptides.

Structure and function information correlating the amino aciddifferences of the exemplary non-naturally occurring (or engineered)polypeptides having CHMO activity of the present disclosure with theirimproved functional capabilities in the biocatalytic reactions of Scheme1 and Scheme 2 are shown below in Tables 2A, 2B, and 2C. The oddnumbered sequence identifiers (i.e., SEQ ID NO) refer to the nucleotidesequence encoding the amino acid sequence provided by the even numberedsequence identifiers, and the sequences are provided in the electronicsequence listing file accompanying this disclosure, which is herebyincorporated by reference herein. The amino acid residue differences arebased on comparison to the reference sequence of SEQ ID NO: 2, which isa wild-type CHMO of Acinetobacter NCIMB9871.

Initial high-throughput (HTP) assays of activity and enantioselectivityin the biocatalytic conversion of Scheme 1 showed that the wild-typeCHMO polypeptide of SEQ ID NO: 2 does not produce the desired productenantiomer of compound (2a) in enantiomeric excess (−52.3% e.e.).However, directed evolution of the gene encoding the wild-typepolypeptide of SEQ ID NO: 2 resulted in several engineered genesencoding polypeptides having CHMO activity capable of producing thedesired product enantiomer of compound (2a) in enantiomer excess. Forexample, the engineered polypeptide of SEQ ID NO: 4 produced by directedevolution was capable the desired product enantiomer of compound (2a) inenantiomeric excess (88% e.e.) and with over 25-fold increased activityrelative to the wild-type.

The engineered CHMO polypeptide sequence of SEQ ID NO: 4 has 10 aminoacid residue differences (98.2% amino acid sequence identity) relativeto the wild-type polypeptide of SEQ ID NO: 2 including the following:D37E, F277I, R278G, M280T, F281I, K326R, F432S, T433G, L435A, and W490L.Further rounds of directed evolution using the gene encoding SEQ ID NO:4 as a starting “backbone” led to the development of the 60 otherexemplary engineered CHMO polypeptides of SEQ ID NO: 6, 8, 10, 12, 14,16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50,52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86,88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116,118, 120, 122, 124, 126, 128, 130, 132, 134, 136, 138, 140, or 142.Additionally, a subset of single residue difference engineered CHMOpolypeptides were generated based on the following 14 positions thatwere identified during directed evolution: X37, X143, X246, X277, X278,X280, X281, X326, X426, X432, X433, X435, X490, and X532. The subsetgenerated included an engineered CHMO polypeptide for each of the 19amino acid differences (relative to the wild-type of SEQ ID NO: 2) ateach of the 14 positions. Each of the single-change engineered CHMOpolypeptides was screened for activity and enantioselectivity in theconversion of the acid substrate of compound (1b) to compound (2b),thereby providing further structural-functional correlation for a subsetof single-amino acid residue changes. As shown in Tables 2A, 2B, 2C, andthe Examples, these engineered polypeptides having CHMO activity arecapable of producing compound (2a) and/or compound (2b) with increasedactivity and in increased enantiomeric excess relative to the wild-typeCHMO. These exemplary engineered CHMO polypeptides also illustrate awide range of amino acid differences that can be introduced across thelength of the wild-type polypeptide sequence which correlate with thisfunctional improvement in the enzyme properties. They also show thatmany of the 10 amino acid differences found in the polypeptide sequenceof the backbone engineered CHMO polypeptide of SEQ ID NO: 4 can bevaried and/or reverted to wild-type while maintaining increased activityover the wild-type and/or the ability to produce the desired enantiomerof compound (2a) in enantiomeric excess. For example, many engineeredCHMO polypeptides having W490Q rather W490L, and/or F280Y rather thanF280T, retain the desired improved properties of increased activity andability to produce compound (2a) in enantiomeric excess. Additionally,the polypeptide of SEQ ID NO: 20 does not include the amino aciddifference F432S yet produces compound (2a) in 99.1% e.e.

Table 2A summarizes the correlation between the structure of theengineered polypeptides having CHMO activity of the present disclosureand the activity and enantioselectivity of these enzymes in carrying outthe biocatalytic conversion of the amide substrate of compound (1a) tothe product of compound (2a) as in Scheme 1. The general SFP assayconditions used to determine amide substrate “Activity” and “% e.e.” assummarized in Table 2A were as follows: 5-10 g/L substrate mixture ofcompound (1a), 3-10 g/L of SFP of the engineered CHMO polypeptide, 1 g/LKRED of SEQ ID NO: 144, 0.3-0.5 g/L NADP, in a solution of 25 mM-100 mMphosphate buffer, 5-10% (v/v) IPA, pH 8.0-8.5, 25° C. reactiontemperature and 24 h reaction time (with 400 rpm stirring). Specificalterations to these general SFP assay conditions were made over therounds of evolution and are noted in Table 2A. Further details of theSFP assays used are described in the Examples.

TABLE 2A Engineered CHMO structure-function correlation in amidesubstrate reaction Amide Substrate Activity SEQ ID relative to NO: Aminoacid differences SEQ ID % (nt/aa) (relative to SEQ ID NO: 2) NO: 4 e.e.3/4 D37E; F277I; R278G; M280T; F281I; K326R; F432S; T433G;  1.0¹ 75L435A; W490L   5/6 D37E; A54V; L143G; V172M; F277I; R278G; M280Y; F281I; 2.8¹ 98 K326R; F432S; T433G; L435A; W490L; L532P   7/8 Q3T; D37E; A54V;L143G; V172M; F277I; R278G; M280Y; F281I;  4.2¹ K326R; F432S; T433G;L435A; W490L; L532P    9/10 Q3T; D37E; A54V; L75M; L143G; V172M; F277I;R278G; M280Y;  9.7² 98.8 F281I; K326R; F432S; T433G; L435A; W490L; L532P11/12 Q3T; D37E; L75M; L143G; F277I; R278G; M280Y; F281I; K326R; 17.4²99.1 L426S; F432S; T433G; L435A; W490L; V503A; L532P 13/14 Q3T; D37E;L75M; F277I; R278G; M280Y; F281I; K326R; F432S; 15.5² T433G; L435A;W490L 15/16 Q3T; D37E; A43G; L75M; L143G; S166G; F277I; R278G; M280Y;26.1² 98.9 F281I; K326R; L426S; F432S; T433G; L435A; W490L; V503A;E512N; L532P 17/18 Q3T; D37E; A43G; L75M; L143G; S166G; F277I; R278G;M280Y; 22.6² F281I; A313E; K326R; L426S; F432S; T433G; L435A; W490L;V503A; L532P 19/20 Q3T; D37E; A43G; L75M; L143G; S166G; F277I; R278G;M280Y; 29.5² 99.1 F281I; K326R; M412L; L426N; T433G; L435A; S489G;W490L; V503A; E512N; L532P 21/22 Q3T; D37E; V42I; A43G; L75M; L143G;S166G; F277I; R278G; 34.7² 98.2 M280Y; F281I; D322G; K326R; L426S;F432S; T433G; L435A; W490L; F492S; V503A; E512N; L532P 23/24 Q3T; D37E;V42I; A43G; L75M; L143G; S166G; F277I; R278G; 34.7² 98.5 M280Y; F281I;D322G; K326R; L426S; F432S; T433G; L435A; N477D; W490L; F492S; V503A;E512N; L532P 25/26 Q3T; D37E; A43G; L75M; L143G; S166G; F277I; R278G;M280Y; 29.5³ 99.2 F281I; A288V; K326R; L426S; F432S; T433G; L435A;W490L; I491V; V503A; Y504I; E512N; L532P 27/28 Q3T; D37E; A43G; L75M;L143G; H163L; S166G; F277I; R278G; 56.0³ 99.8 M280Y; F281I; A288V;D322G; K326R; A382R; L426S; F432S; T433G; L435A; N477D; W490L; I491V;V503A; Y504I; E512N; L532P 29/30 Q3T; D37E; A43G; L75M; L143G; S166G;F277I; R278G; M280Y; 58.9³ 99.7 F281I; A288V; D322G; K326R; V348A;L426S; F432S; T433G; L435A; N477D; S489G; W490L; I491V; V503A; Y504I;E512N; L532P; K538E; 31/32 Q3T; D37E; V42I; A43G; L75M; L143G; S166G;F277I; R278G; 32.4³ 99.9 M280Y; F281I; A288V; K326R; L426S; F432S;T433G; L435A; N477D; W490L; I491V; V503A; Y504I; E512N; L532P 33/34 Q3T;D37E; V42I; A43G; L75M; L143G; H163L; S166G; G176S; 56.0³ 99.8 F277I;R278G; M280Y; F281I; A288V; D322G; K326R; A382R; L426S; F432S; T433G;L435A; N477D; S489G; W490L; I491V; V503A; Y504I; E512N; L532P 35/36 Q3T;D37E; A43G; L75M; L143G; H163L; S166G; G176S; F277I; 50.1³ 99.6 R278G;M280Y; F281I; A288V; D322G; K326R; L426S; F432S; T433G; L435A; N477D;W490L; I491V; V503A; Y504I; E512N; L532P 37/38 Q3T; D37E; A43G; L75M;L143G; S166A; F277I; R278G; M280Y; 58.9³ 99.8 F281I; A288V; K326R;E364K; K395R; M412L; L426S; F432S; T433G; L435A; W490L; I491V; V503A;Y504I; E512N; L532P 39/40 Q3T; D37E; A43G; L75M; L143G; S166A; F277I;R278G; M280Y; 44.2³ 99.6 F281I; A288V; K326R; K395R; L426S; F432S;T433G; L435A; W490L; I491V; V503A; Y504I; E512N; L532P ¹Substrate: 5g/L; CHMO: 3 g/L; NADP: 0.5 g/L; IPA: 10%; 25 mM phosphate, pH 8.5.²Substrate: 10 g/L; CHMO: 10 g/L; NADP: 0.3 g/L; IPA: 5%; 100 mMphosphate, pH 8.0. ³Substrate: 10 g/L; CHMO: 5 g/L; NADP: 0.3 g/L; IPA:5%; 100 mM phosphate, pH 8.0.

Table 2B summarizes the correlation between the structure of theengineered polypeptides having CHMO activity of the present disclosureand the activity and enantioselectivity of these enzymes in carrying outthe biocatalytic conversion of the acid substrate of compound (1b) tothe product of compound (2b) as in Scheme 2. The general SFP assayconditions used to determine acid substrate “Activity” and “% e.e.” assummarized in Table 2B were as follows: 10-100 g/L substrate mixture ofcompound (1b), 5-10 g/L of SFP of the engineered CHMO polypeptide, 1 g/LKRED of SEQ ID NO: 144 or 146, 0.2-0.3 g/L NADP, in a solution of 100 mMphosphate buffer or TEA buffer, 5% (v/v) IPA, pH 8.3 or pH 9.0, 25° C.reaction temperature and 24 h reaction time (with 400 rpm stirring).Specific alterations to these general SFP assay conditions were madeover the rounds of evolution and are noted in Table 2B. Further detailsof the SFP assays used are described in the Examples.

TABLE 2B Engineered CHMO structure-function correlation in acidsubstrate reaction Activity relative SEQ ID to SEQ NO: Amino aciddifferences ID NO: % (nt/aa) (relative to SEQ ID NO: 2) 38 e.e. 37/38Q3T; D37E; A43G; L75M; L143G; S166A; F277I; R278G; M280Y;    1.0¹ 94F281I; A288V; K326R; E364K; K395R; M412L; L426S; F432S; T433G; L435A;W490L; I491V; V503A; Y504I; E512N; L532P 41/42 Q3T; D37E; A43G; L75M;D99V; L143G; E161D; S166A; F174I;    8.2¹ 98.7 T273A; F277I; R278G;M280Y; F281I; A288V; D322M; Y324K; K326R; E364K; K395R; M412L; L426S;F432S; T433G; L435A; W490L; I491V; V503A; Y504I; E512N; L532P 43/44 Q3T;D37E; A43G; L75M; D99V; L143G; S166A; F174I; T273S;    8.9¹ 95 F277I;R278G; M280Y; F281I; A288V; D322M; K326R; E364K; K395R; M412L; L426S;F432S; T433G; L435A; W490L; I491V; V503A; Y504I; E512N; L532P 45/46 Q3T;D37E; A43G; L75M; E123A; L143G; S166A; F174I; T273S;    9.9¹ 94.2 F277I;R278G; M280Y; F281I; A288V; D322M; K326R; E364K; K395R; M412L; L426S;F432S; T433G; L435A; W490L; I491V; V503A; Y504I; E512N; L532P 47/48 Q3T;D37E; A43G; L75M; D99V; L143G; E161D; S166A; F174I;    8.7¹ 99 T273S;F277I; R278G; M280Y; F281I; A288V; Y324K; K326R; E364K; K395R; M412L;L426S; F432S; T433G; L435A; W490L; I491V; V503A; Y504I; E512N; L532P49/50 Q3T; D37E; A43G; L75M; D99V; L143G; E161D; S166G; F174I;    23.5¹98.5 T273S; F277I; R278G; M280Y; F281I; A288V; Y324K; K326R; E364K;K395R; M412L; L426S; F432S; T433G; L435A; K486E; W490L; I491V; V503A;Y504I; E512N; L532P 51/52 Q3T; D37E; A43G; L75M; D99V; L143G; E161D;S166A; F174I;    19.1¹ 98.5 K227E; T273S; F277I; R278G; M280Y; F281I;A288V; Y324K; K326R; E364K; K395R; M412L; L426S; F432S; T433G; L435A;W490L; I491V; V503A; Y504I; E512N; L532P 53/54 Q3T; D37E; A43G; L75M;V82A; D99V; V110M; L143G; E161D;    20.0¹ 98.7 S166A; F174I; T273S;F277I; R278G; M280Y; F281I; A288V; Y324K; K326R; E364K; K395R; M412L;L426S; F432S; T433G; L435A; W490L; I491V; V503A; Y504I; E512N; L532P55/56 Q3T; D37E; A43G; L75M; D99V; L143G; E161D; S166A; F174I;    14.8¹99.7 T273S; F277I; R278G; M280Y; F281I; A288V; Y324K; K326R; E364K;K395R; M412L; L426S; G430R; F432S; T433G; L435A; W490L; I491V; V503A;Y504I; E512N; L532P 57/58 Q3T; D37E; A43G; L75M; V82A; D99V; L143G;E161D; S166A;    18.3¹ 98.5 F174I; T273S; F277I; R278G; M280Y; F281I;A288V; Y324K; K326R; E364K; K395R; M412L; L426S; F432S; T433G; L435A;W490L; I491V; V503A; Y504I; E512N; L532P 59/60 Q3T; D37E; A43G; L75M;K79T; V82A; D99V; L143G; E161D;    84.4¹ 98.7 S166A; F174I; T273S;F277I; R278G; M280Y; F281I; A288V; Y324K; K326R; E364K; K395R; M412L;L426S; F432S; T433G; L435A; W490L; I491V; V503A; Y504I; E512N; L532P61/62 Q3T; D37E; A43G; L75M; K79T; D99V; R135K; L143G; E161D;    20.9¹97.8 S166A; D171G; F174I; I182V; T273S; F277I; R278G; M280Y; F281I;A288V; I314T; Y324K; K326R; E364K; M373V; K395R; M412L; L426S; F432S;T433G; L435A; W490L; I491V; V503A; Y504I; E512N; L532P 63/64 Q3T; D37E;A43G; L75M; D99V; L143G; E161D; S166A; F174I;    59.2¹ 99.7 T273S;F277I; R278G; M280Y; F281I; A288V; Y324K; K326R; E364K; K395R; M412L;L426S; G430R; F432S; T433G; L435A; T472I; I478L; W490L; I491V; V503A;Y504I; E512N; L532P 65/66 Q3T; D37E; A43G; L75M; K79T; V82I; D99V;L143G; E161D;    74.8¹ 99.7 H163Y; S166A; F174I; T273S; F277I; R278G;M280Y; F281I; A288V; N290D; M319T; Y324K; K326R; E364K; K395R; M412L;L426S; G430R; F432S; T433G; L435A; W490L; I491V; V503A; Y504I; E512N;L532P 67/68 Q3T; D37E; A43G; L75M; K79T; V82A; D99V; L143G; E161D;  270.6¹ 98.3 H163Y; S166A; F174I; T273S; F277I; R278G; M280Y; F281I;A288V; Y324K; K326R; E364K; K395R; M412L; L426S; F432S; T433G; L435A;T472I; W490L; I491V; V503A; Y504I; E512N; L532P 69/70 Q3T; D37E; A43G;L75M; K79T; D99V; L143G; E161D; S166A;   123.5¹ 98.2 F174I; T273S;F277I; R278G; M280Y; F281I; A288V; Y324K; K326R; E364K; K395R; M412L;L426S; F432S; T433G; L435A; T472I; W490L; I491V; V503A; Y504I; E512N;L532P 71/72 Q3T; D37E; A43G; L75M; D99V; L143G; E161D; S166A; F174I;   13.9¹ 97 T273S; F277I; R278G; M280Y; F281I; Y324K; K326R; K395R;M412L; L426S; F432S; T433G; L435A; W490L; I491V; V503A; Y504I; E512N;L532P 73/74 Q3T; D37E; A43G; L75M; D99V; L143G; E161D; S166G; F174I;   19.1¹ 98 T273S; F277I; R278G; M280Y; F281I; A288V; Y324K; K326R;K395R; M412L; L426S; F432S; T433G; L435A; W490L; I491V; V503A; Y504I;E512N; L532P 75/76 Q3T; D37E; A43G; L75M; D99V; L143G; E161D; S166A;F174I;    14.8¹ 99.2 T273S; F277I; R278G; M280Y; F281I; A288V; Y324K;K326R; E364K; K395R; M412L; L426S; F432S; T433G; L435A; F484C; W490L;I491V; V503A; Y504I; E512N; L532P 77/78 Q3T; D37E; A43G; L75M; K79T;V82A; D99V; V110M; L143G;   522¹ 99.7 E161D; S166A; F174I; S208T; G216S;T273S; F277I; R278G; M280Y; F281I; A288L; Y324K; K326R; E364K; K395R;M412L; L426S; G430R; F432S; T433G; L435A; W490L; I491V; F492K; V503A;Y504I; F505K; E512N; L532P 79/80 Q3T; D37E; A43G; L75M; K79T; D99V;L143G; E161D; S166A;   566¹ 99.1 F174I; G216S; T273S; F277I; R278G;M280Y; F281I; A288V; Y324K; K326R; E364K; K395R; M412L; L426S; F432S;T433G; L435A; S438R; W490L; I491V; F492K; V503A; Y504I; F505K; E512N;L532P 81/82 Q3T; D37E; A43G; L75M; K79T; V82A; D99V; V110M; L143G;  870² 99.8 E161D; S166A; F174I; I192V; S208T; G216S; T273S; F277I;R278G; M280Y; F281I; A288V; Y324K; K326R; E364K; K395R; M412L; L426S;F432S; T433G; L435A; W490L; I491V; F492K; V503A; Y504I; F505K; E512N;L532P 83/84 Q3T; D37E; A43G; L75M; V82A; D99V; V110M; L143G; E161D;  696² 99.9 S166A; F174I; G216S; T273S; F277I; R278G; M280Y; F281I;A288V; Y324K; K326R; E364K; K395R; M412L; L426S; F432S; T433G; L435A;W490L; I491V; V503A; Y504I; F505K; E512N; L532P 85/86 Q3T; D37E; A43G;L75M; K79T; V82A; D99V; L143G; E161D;   539² 99.8 S166A; F174I; S208T;G216S; T273S; F277I; R278G; M280Y; F281I; A288V; Y324K; K326R; E364K;K395R; M412L; L426S; G430R; F432S; T433G; L435A; W490L; I491V; V503A;Y504I; E512N; L532P 87/88 Q3T; D37E; A43G; L75M; K79T; V82A; D99V;V110M; L143G;   261² 99.7 E161D; S166G; F174I; S208T; G216S; K227E;T273C; F277I; R278G; M280Y; F281I; A288L; Y324K; K326R; N336S; K395R;M412L; L426S; F432S; T433G; L435A; T472I; F484C; K486E; W490L; I491V;F492K; V503A; Y504I; F505K; E512N; L532P 89/90 Q3T; D37E; A43G; L75M;K79T; V82A; D99V; V110M; L143G;   7830³ 99.7 E161D; S166A; F174I; S208T;G216S; T273C; F277I; R278G; M280Y; F281I; Y324K; K326R; E364K; K395R;M412L; L426S; F432S; T433G; L435A; T472I; K486E; W490L; I491V; F492K;V503A; Y504I; F505K; E512N; L532P 91/92 Q3T; D37E; A43G; L75M; K79T;V82A; D99V; V110M; L143G;  19140³ 99.8 E161D; S166A; F174I; S208T;G216S; T273C; F277I; R278G; M280Y; F281I; A288L; Y324K; K326R; E364K;K395R; M412L; L426S; F432S; T433G; L435A; T472I; K486E; W490L; I491V;F492K; V503A; Y504I; F505K; E512N; L532P; Q539E 93/94 Q3T; D37E; A43G;L75M; K79E; V82A; D99V; V110M; L143G;  21750³ 99.8 E161D; S166A; F174I;I192V; S208T; G216S; T273C; F277I; R278G; M280Y; F281I; A288L; Y324K;K326R; K395R; M412L; L426S; F432S; T433G; L435A; T472I; F484C; K486E;W490L; I491V; F492K; V503A; Y504I; F505K; E512N; L532P 95/96 Q3T; D37E;A43G; L75M; K79T; V82A; D99V; V110M; L143G;  29580³ 99.8 E161D; S166A;F174I; S208T; G216S; T273S; F277I; R278G; M280Y; F281I; A288L; I314L;Y324K; K326R; K395R; M412L; L426S; F432S; T433G; L435A; T472I; F484C;K486E; W490L; I491V; F492K; V503A; Y504I; F505K; E512N; L532P 97/98 Q3T;D37E; A43G; L75M; K79T; V82A; D99V; V110M; L143G;  13050³ E161D; S166A;F174I; I192V; S208T; G216S; T273S; F277I; R278G; M280Y; F281I; Y324K;K326R; K395R; M412L; L426S; F432S; T433G; L435A; T472I; K486E; W490L;I491V; F492K; V503A; Y504I; F505K; E512N; L532P  99/100 Q3T; D37E; A43G;L75M; K79E; V82A; D99V; V110M; L143G;  21750³ 99.7 E161D; S166G; F174I;S208T; G216S; T273C; F277I; R278G; M280Y; F281I; A288L; I314L; Y324K;K326R; K395R; M412L; L426S; F432S; T433G; L435A; T472I; F484C; K486E;W490L; I491V; F492K; V503A; Y504I; F505K; E512N; L532P 101/102 Q3T;D37E; A43G; L75M; K79T; V82A; D99V; V110M; L143G;  10440³ 99.8 E161D;S166A; F174I; S208T; G216S; T273S; F277I; R278G; M280Y; F281I; A288V;Y324K; K326R; K395R; M412L; L426S; F432S; T433G; L435A; T472I; F484C;K486E; W490L; I491V; F492K; V503A; Y504I; F505K; E512N; L532P 103/104Q3T; D37E; A43G; L75M; K79T; V82A; D99V; V110M; L143G;   5220³ 99.8E161D; S166A; F174I; I192V; S208T; G216S; T273S; F277I; R278G; M280Y;F281I; A288V; Y324K; K326R; K395R; M412L; L426S; F432S; T433G; L435A;T472I; K486E; W490L; I491V; F492K; V503A; Y504I; F505K; E512N; L532P105/106 Q3T; D37E; A43G; L75M; K79T; V82A; D99V; V110M; L143G;  26100³99.7 E161D; S166A; F174I; S208T; G216S; T273C; F277I; R278A; M280Y;F281I; Y324K; K326R; E364K; K395R; M412L; L426S; F432S; T433G; L435A;T472I; K486E; W490L; I491V; F492K; V503A; Y504I; F505K; E512N; L532P107/108 Q3T; D37E; A43G; L75M; K79T; V82A; D99V; V110M; L143G;  50895⁴99.8 E161D; S166A; F174I; S208T; G216S; K234D; T273C; F277I; R278G;M280Y; F281I; Y324K; K326R; E364K; K395R; M412L; L426S; F432S; T433G;L435A; S438M; T472I; K486E; W490Q; I491V; V503A; Y504I; F505K; E512N;L532P 109/110 Q3T; D37E; A43G; L75M; K79T; V82A; D99V; V110M; L143G; 23490⁴ 99.8 E161D; S166A; F174I; S208T; G216S; K227E; T273C; F277I;R278G; M280Y; F281I; Y324K; K326R; E364K; K395R; M412L; L426S; F432S;T433G; L435A; S438M; T472I; F484C; K486E; W490Q; I491V; V503A; Y504I;F505K; E512N; L532P 111/112 Q3T; D37E; A43G; L75M; K79T; V82A; D99V;V110M; L143G;  23490⁴ 99.9 E161D; S166A; F174I; S208T; G216S; T273C;F277I; R278G; M280Y; F281I; K310E; Y324K; K326R; E364K; K395R; M412L;L426S; F432S; T433G; L435A; S438M; T472I; K486E; W490Q; I491V; F492K;V503A; Y504I; F505K; E512N; L532P 113/114 Q3T; D37E; A43G; L75M; K79T;V82A; D99V; V110M; L143G;  34452⁴ 99.9 E161D; S166A; F174I; S208T;G216S; K227D; T273C; F277I; R278G; M280Y; F281I; K310E; Y324K; K326R;E364K; K395R; M412L; L426S; F432S; T433G; L435A; S438M; T472I; K486E;W490L; I491V; F492K; V503A; Y504I; F505K; E512N; L532P 115/116 Q3T;D37E; A43G; L75M; K79T; V82A; D99V; V110M; L143G;  117059⁵ 99.9 E161D;S166A; F174I; S208T; G216S; K234D; T273S; F277I; R278G; M280Y; F281I;Y324K; K326R; E364K; K395R; M412L; L426S; F432S; T433G; L435A; S438M;T472I; F484C; K486E; W490Q; I491V; V503A; Y504I; F505K; E512N; L532P117/118 Q3T; D37E; A43G; L75M; K79T; V82A; D99V; V110M; L143G;  61074⁵99.9 E161D; S166A; F174I; S208T; G216S; K234D; T273C; F277I; R278G;M280Y; F281I; Y324K; K326R; E364K K395R; M412L; L426S; F432S; T433G;L435A; S438M; T472I; K486E; W490Q; I491V; F492K; V503A; Y504I; F505K;E512N; L532P 119/120 Q3T; D37E; A43G; L75M; K79T; V82A; D99V; V110M;L143G;  421411⁵ E161D; S166A; V172A; F174I; S208T; G216S; K234D; A243K;A245G; T273S; F277I; R278G; M280Y; F281I; M319T; Y324K; A325Y; K326R;K395R; M412L; L426S; F432S; T433G; L435A; S438M; T472I; K486E; W490Q;I491V; F492K; N501D; V503A; Y504I; F505K; E512N; L532P 121/122 Q3T;D37E; A43G; L75M; K79T; V82A; D99V; V110M; L143G;  374587⁵ E161D; S166A;V172A; F174I; S208T; G216S; K234D; A243K; A245G; T273S; F277I; R278G;M280Y; F281I; M319T; Y324K; K326R; K395R; M412L; L426S; F432S; T433G;L435A; S438M; T472I; K486E; W490Q; I491V; F492K; V503A; Y504I; F505K;E512N; L532P 123/124 Q3T; D37E; A43G; L75M; K79T; V82A; D99V; V110M;L143G;  280940⁵ E161D; S166A; V172A; F174I; S208T; G216S; K234D; A243K;A245G; T273S; F277I; R278G; M280Y F281I; M319L; Y324K; A325Y; K326R;E364K; K395R; M412L; L426S; F432S; T433G; L435A; S438M; T472I; K486E;W490Q I491V; V503A; Y504I; F505K; E512N; L532P 125/126 Q3T; D37E; A43G;L62V; L75M; K79T V82A; D99V; V110M;  374587⁵ 99.9 L143G; E161D; S166A;F174I; S208T; G216S; K234D; A243K; A245G; T273S; G275S; F277I; R278G;M280Y; F281I; Y324K; K326R; L329V; E364K; K395R; M412L; L426S; F432S;T433G; L435A; S438M; T472I; F484C; K486E; W490Q; I491V; V503A; Y504I;F505K; E512N; L532P 127/128 Q3T; D37E; A43G; L62V; L75M; K79T V82A;D99V; V110M;  374587⁵ L143G; E161D; S166A; F174I; S208T; G216S; K234D;A243K; A245G; T273S; G275N; F277I; R278G; M280Y; F281I; Y324K; K326R;L329V; E364K; K395R; M412L; L426S; F432S; T433G; L435A; S438M; T472I;F484C; K486E; W490Q; I491V; V503A; Y504I; F505K; E512N; L532P 129/130Q3T; D37E; A43G; L75M; K79T; V82A; K89M; D99V; V110M;  547834⁶ 99.8A118V; L143G; E161D; S166A; V172A; F174I; S208T; G216I; K234D; A243K;A245G; K264Y; T273S; F277I; R278G; M280Y; F281I; M291R; K310H; M319T;Y324K; A325Y; K326R; K395R; M412L; L426S; F432S; T433G; L435A; S438M;T472I; K486E; W490Q; I491V; F492K; N501D; V503A; Y504I; F505K; E512N;L532P 131/132 Q3T; D37E; T40G; A43G; S74E; L75M K79T; V82A; K89M; D99V; 602617⁶ V110M; A118V; L143G; E161D; S166A; V172A; F174I; S208T; G216I;K234D; A243K; A245G; K264Y; T273S; F277I; R278G; M280Y; F281I; M291R;M319T; Y324K; A325F; K326R; K395R; M412L; L426S; F432S; T433G; L435A;S438M; T472I; K486E; W490Q; I491V; F492K; G498N; N501D; V503A; Y504I;F505K; E512N; L532P 133/134 Q3T; K32E; D37E; A43G; L75M; K79T; V82A;K89N; D99V; V110M;  657401⁷ 99.8 A118V; L143S; E161D; S166A; V172A;F174I; S208T; G216I; P219V; K234D; A243K; A245G; K264Y; T273S; G275A;F277I; R278G; M280Y; F281I; M291R; K310H; M319T; Y324K; A325Y; K326R;K362S; K395R; M412L; L426S; F432S; T433G; L435A; S438M; T472I; K486E;W490Q; I491V; F492K; N501D; V503A; Y504I; F505K; E512N; L532P 135/136Q3T; D37E; A43G; L75M; K79T; V82A; G84H; K89N; D99V; 1018971⁸ 99.8V110M; A118V; L143S; E161D; S166A; V172A; F174I; S208T; G216I; P219V;K234D; A243K; A245G; K264Y; T273S; G275A; F277I; R278A; M280Y; F281I;M291R; K310H; M319T; Y324K; A325Y; K326R; K362S; K395R; M412L; L426S;F432S; T433G; L435A; S438M; T472I; Q473D; N477D; F484L; K486E; W490Q;I491V; F492K; G498N; N501D; V503A; Y504I; F505K; E512N; L532P 137/138Q3T; D37E; A43G; L75M; K79T; V82A; G84H; K89N; D99V;  815177⁸ V110M;A118V; L143S; E161D; S166A; V172A; F174I; S208T; G216I; P219V; K234D;A243K; A245G; K264Y; T273S; G275A; F277I; R278A; M280Y; F281I; M291R;K310H; M319T; Y324K; A325Y; K326R; K395R; M412L; L426S; F432S; T433G;L435A; S438M; T472I; N477D; F484L; K486E; W490Q; I491V; F492K; N501D;V503A; Y504I; F505K; E512N; L532P 139/140 Q3T; D37E; A43G; L75M; K79T;V82A; K89N; D99V; V110M;  992675⁸ A118V; L143S; E161D; S166A; V172A;F174I; S208T; G216I; P219V; K234D; A243K; A245G; K264Y; T273S; G275A;F277I; R278A; M280Y; F281I; M291R; K310H; M319T; Y324K; A325F; K326R;K395R; M412L; L426S; F432S; T433G; L435A; S438M; T472I; Q473D; N477D;F484L; K486E; W490Q; I491V; F492K; G498N; N501D; V503A; Y504I; F505K;E512N; L532P 141/142 Q3T; D37E; T40G; A43G; L75M; K79T; V82A; G84H;K89N; D99V;  940083⁸ V110M; A118V; L143S; E161D; S166A; V172A; F174I;S208T; G216I; P219V; K234D; A243K; A245G; K264Y; T273S; G275A; F277I;R278G; M280Y; F281I; M291R; M319T; Y324K; A325F; K326R; K395R; M412L;L426S; F432S; T433G; L435A; S438M; T472I; Q473D; N477D; F484L; K486E;W490Q; I491V; F492K; G498N; N501D; V503A; Y504I; F505K; E512N; L532P¹Substrate: 10 g/L; CHMO: 10 g/L; NADP: 0.3 g/L; 100 mM phosphate, pH9.0. ²Substrate: 25 g/L; CHMO: 10 g/L; NADP: 0.2 g/L; 100 mM TEA, pH8.3. ³Substrate: 35 g/L; CHMO: 5 g/L; NADP: 0.2 g/L; 100 mM TEA, pH 8.3.⁴Substrate: 50 g/L; CHMO: 5 g/L; NADP: 0.2 g/L; 100 mM TEA, pH 8.3.⁵Substrate: 60 g/L; CHMO: 5 g/L; NADP: 0.2 g/L; 100 mM TEA, pH 8.3.⁶Substrate: 30 g/L; CHMO: 0.5 g/L; NADP: 0.2 g/L; 100 mM TEA, pH 9.0;PEG200: 10% (v/v); Temperature: 35° C. ⁷Substrate: 30 g/L; CHMO: 0.5g/L; NADP: 0.2 g/L; 100 mM TEA, pH 8.5; PEG200: 10% (v/v); Temperature:35° C. ⁸Substrate: 100 g/L; CHMO: 2 g/L; NADP: 0.2 g/L; 100 mM TEA, pH8.5; PEG200: 10% (v/v); Temperature: 35° C.

In some embodiments, the non-naturally occurring (or engineered)polypeptides having CHMO activity of the present disclosure comprise anamino acid sequence selected from any one of SEQ ID NO: 4, 6, 8, 10, 12,14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48,50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84,86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116,118, 120, 122, 124, 126, 128, 130, 132, 134, 136, 138, 140, or 142; oran amino acid sequence having at least 80%, 85%, 86%, 87%, 88%, 89%,90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to any oneof the above-listed exemplary sequences. In some embodiments, thenon-naturally occurring polypeptide having CHMO activity is capable ofconverting compound (1a) to compound (2a) in enantiomeric excess and/orcompound (1b) to compound (2b) in enantiomeric excess under suitablereaction conditions. For example, in some embodiments, the presentdisclosure provides an engineered polypeptide having CHMO activitycapable of converting compound (1a) to compound (2a) and/or compound(1b) to compound (2b) in enantiomeric excess under suitable conditions,in which the amino acid sequence of the polypeptide has at least 96%,97%, 98%, or 99% identity to SEQ ID NO: 38. In some embodiments, thepresent disclosure provides an engineered polypeptide having CHMOactivity capable of converting compound (1a) to compound (2a) and/orcompound (1b) to compound (2b) in enantiomeric excess under suitableconditions, in which the amino acid sequence of the polypeptide has atleast 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ IDNO: 136.

Table 2C further summarizes the correlation between the structure of theengineered polypeptides having CHMO activity of the present disclosureand the activity and enantioselectivity of these enzymes in carrying outthe biocatalytic conversion of the acid substrate of compound (1b) tothe product of compound (2b). The single residue difference engineeredCHMO polypeptides summarized in Table 2C were generating all 19 aminoacid residue differences at 14 positions identified during directedevolution (X37, X143, X246, X277, X278, X280, X281, X326, X426, X432,X433, X435, X490, and X532) and screening each of the single-changeengineered CHMO polypeptides in a HTP assay for improved activity andenantioselectivity in the conversion of the acid substrate of compound(1b) to compound (2b). Only single-change engineered CHMO polypeptidesexhibiting at 2-fold improved activity relative to wild-type of SEQ IDNO: 2 in the conversion of compound (1b) to compound (2b) (or theopposite enantiomer of compound (2b)) are listed in Table 2C.Consequently, certain amino acid residue differences that appear in theengineered CHMO polypeptides of Tables 2A and 2B do not appear in Table2C (e.g., D37E).

The HTP assay conditions and HPLC analysis used to determine acidsubstrate “Activity FIOP” and “% e.e.” as summarized in Table 2C weregenerally as described in Example 1—assay in a 96-well deep well plateas a 24 h assay in 0.1 M TEA, pH 9 at room temperature. The assay wasinitiated by adding to each deep-well the following solutions: (1) 20 μLof a KRED-cofactor solution containing 1 g/L KRED polypeptide of SEQ IDNO: 144 and 0.2 g/L NADP⁺ in 0.1 M TEA, pH 9; (2) 130 μL of E. colicell-lysate containing the engineered CHMO polypeptide in 0.1 M TEA, pH9 (prepared as in Example 1); (3) 40 μL of substrate stock containing 1g/L of compound (1b) in 0.1 M TEA, pH 9; and (4) 10 μL of IPA. The platewas heat sealed for 3 s at 180° C., and then shaken at 200 rpm and 25°C. for ˜20-24 h. Further details of HTP assay HPLC analysis methods usedare described in the Examples.

TABLE 2C Activity Amino acid difference Fold-Improvement % ee (relativeto SEQ ID NO: 2) (relative to SEQ ID NO: 2) of R-isomer None (Wild-type)1.0 25.3 L143C 2.8 33.6 L143E 3.7 40.1 L143F 8.0 40.3 L143G 2.5 68.0L143H 14.9 38.6 L143K 1.8 80.7 L143M 3.1 67.6 L143P 4.5 51.7 L143Q 4.750.1 L143S 3.6 62.0 L143T 1.8 35.0 L143W 17.0 89.5 F246A 6.8 77.0 F246E3.7 76.6 F246G 1.8 75.2 F246I 10.6 86.4 F246L 17.0 97.9 F246N 2.1 23.5F246P 4.9 84.8 F246S 5.5 76.0 F246T 4.7 55.8 F246V 14.1 85.0 F277C 14.4−51.7 F277D 1.3 −32.4 F277E 1.3 9.4 F277G 2.9 3.5 F277H 11.3 −14.3 F277L19.8 9.9 F277M 10.6 −62.9 F277P 19.8 −94.8 F277S 13.2 −79.1 F277T 17.3−53.0 F277V 19.9 −65.9 F277W 6.5 9.8 R278A 2.3 36.5 R278C 1.4 15.0 R278G3.3 57.9 R278H 6.1 22.8 R278K 4.1 2.6 R278N 2.1 89.9 R278Q 3.1 49.9R278S 2.7 41.5 R278T 3.1 12.2 R278V 1.3 16.7 M280L 3.8 −30.8 M280T 1.1−48.4 M280W 14.1 −24.1 F281A 1.5 −43.6 F281C 1.6 −33.0 F281H 6.6 −86.5F281K 2.0 −47.7 F281L 1.6 −38.7 F281M 2.0 −57.1 F281N 1.4 −61.0 F281R1.6 −56.3 F281T 2.3 −59.8 F281V 1.7 −53.4 F281W 3.5 2.5 F281Y 3.0 −26.1K326A 13.3 −13.8 K326C 19.9 3.9 K326D 12.9 −25.4 K326E 16.0 −38.8 K326F15.3 −30.0 K326G 17.3 22.6 K326H 2.3 29.8 K326L 20.5 21.5 K326M 20.7−28.1 K326N 8.2 −3.9 K326P 11.1 9.5 K326R 6.0 13.8 K326S 14.2 0.8 K326T14.6 −2.5 K326V 20.5 −10.5 K326W 20.4 −26.2 L426G 2.5 41.8 L426Q 2.357.2 L426T 5.0 82.0 F432A 3.4 15.0 F432E 1.4 52.6 F432I 11.4 59.4 F432K3.0 21.5 F432L 13.2 77.5 F432N 5.4 27.3 F432Q 18.0 87.3 F432S 4.1 64.4F432T 1.9 68.8 F432V 17.9 55.5 F432W 14.4 89.5 T433A 5.1 90.7 T433S 6.592.6 L435G 12.8 57.4 L435K 2.0 91.5 L435V 2.5 46.5 L435Y 8.7 99.2 W490A16.7 30.9 W490C 17.3 6.2 W490D 17.2 23.5 W490E 17.0 26.2 W490G 16.4 44.6W490I 17.2 8.7 W490K 17.8 32.6 W490L 17.3 14.1 W490M 16.6 32.0 W490N16.6 41.8 W490R 17.2 27.4 W490S 15.9 41.3 W490Y 16.2 21.7 L532M 2.8 65.1

It is contemplated that any of the single residue difference engineeredCHMO polypeptides could be used as a starting backbone for furtherdirected evolution to generate engineered CHMO polypeptides thatcomprise the single residue difference, the correlated improvedfunctional property, and one or more additional amino acid differences,such as any residue difference or combination of residue differenceslisted in Tables 2A or 2B.

As shown in Table 2C, engineered CHMO polypeptides having at least oneof the following amino acid differences relative to SEQ ID NO: 2 arecapable of converting the acid substrate compound (1b) to compound (2b)(R-enantiomer) or its opposite enantiomer compound (S-enantiomer) withat least 2-fold improved activity relative to the wild-type polypeptideof SEQ ID NO: 2: X143C, E, F, G, H, K, M, P, Q, S, T, or W; X246A, E, G,I, L, N, P, S, T, or V; X277C, D, E, G, H, L, M, P, S, T, V, or W;X278A, C, G, H, K, N, Q, S, T, or V; X280L, T, or W; X281A, C, H, K, L,M, N, R, T, V, W, or Y; X326A, C, D, E, F, G, H, L, M, N, P, R, S, T, V,or W; X426G, Q, or T; X432A, E, I, K, L, N, Q, S, T, V, or W; X433A, orS; X435G, K, V, or Y; X490A, C, D, E, G, I, K, L, M, N, R, S, or Y;X532M.

Also as shown in Table 2C, engineered CHMO polypeptides having at leastone of the following amino acid differences relative to SEQ ID NO: 2 arecapable of converting the acid substrate of compound (1b) to theR-enantiomer compound (2b) in at least 50% ee: X143G, K, M, P, Q, S, orW; X246A, E, G, I, L, P, S, T, or V; X278G, or N; X426Q, or T; X432E, I,L, Q, S, T, V, or W; X433A, or S; X435G, K, or Y; X532M.

Further, as shown in Table 2C, engineered CHMO polypeptides having atleast one of the following amino acid differences relative to SEQ ID NO:2 are capable of converting the acid substrate of compound (1b) to theopposite enantiomer of compound (2b) (S-enantiomer) in at least 50% ee:X277C, M, P, S, T, or V; X281H, M, N, R, T, or V.

Accordingly, in some embodiments the present disclosure provides anon-naturally occurring (or engineered) polypeptide having cyclohexanonemonooxygenase (CHMO) activity wherein the amino acid sequence of thepolypeptide has at least 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%,93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NO: 2and one or more amino acid differences relative to SEQ ID NO: 2 selectedfrom the following: X143C, E, F, G, H, K, M, P, Q, S, T, or W; X246A, E,G, I, L, N, P, S, T, or V; X277C, D, E, G, H, L, M, P, S, T, V, or W;X278A, C, G, H, K, N, Q, S, T, or V; X280L, T, or W; X281A, C, H, K, L,M, N, R, T, V, W, or Y; X326A, D, E, F, G, H, L, M, N, P, R, V, or W;X426G, Q, or T; X432E, I, K, N, Q, T, V, or W; X433S; X435G, K, V, or Y;X490A, C, D, E, G, I, L, M, N, S, or Y; and X532M. In some embodiments,the polypeptide is capable of converting the acid substrate compound(1b) to compound (2b) (R-enantiomer) or its opposite enantiomer compound(S-enantiomer) with at least 2-fold improved activity relative to thewild-type polypeptide of SEQ ID NO: 2. In some embodiments, the aminoacid sequence comprises one or more amino acid differences relative toSEQ ID NO: 2 selected from: X143G, K, M, P, Q, S, or W; X246A, E, G, I,L, P, S, T, or V; X278G, or N; X426Q, or T; X432E, I, L, Q, S, T, V, orW; X433A, or S; X435G, K, or Y; and X532M, and in such embodiments, thepolypeptide is capable of converting the acid substrate of compound (1b)to the R-enantiomer compound (2b) in at least 50% ee.

In some embodiments of the non-naturally occurring (or engineered)polypeptide having CHMO activity, the polypeptide amino acid sequencecomprises one or more amino acid differences relative to SEQ ID NO: 2selected from: X143G; X278G; X326R; and X490L. Further, in someembodiments, the amino acid sequence comprises at least the followingamino acid differences relative to SEQ ID NO: 2: X277I; X278A, or G;X280T or Y; X281I; X326R; and X490L or X490Q. In additional embodiments,the polypeptide amino acid sequence may further comprise at least onecombination of amino acid differences relative to SEQ ID NO: 2 selectedfrom the exemplary polypeptides listed in Tables 2A and 2B (as describedbelow).

As shown in Tables 2A and 2B, the following amino acid differencesrelative to SEQ ID NO: 2 are associated with the increased activity andenantioselectivity properties found in all of the exemplary CHMOpolypeptides: X37E; X277I; X278A or X278G; X280T or X280Y; X281I; X326R;and X490L or X490Q. Accordingly, in some embodiments, the presentdisclosure provides a non-naturally occurring polypeptide having CHMOactivity wherein the amino acid sequence of the polypeptide has: (a)sequence identity of at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%,98%, or 99% to any one of SEQ ID NO: 4, 6, 8, 10, 12, 14, 16, 18, 20,22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56,58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92,94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122,124, 126, 128, 130, 132, 134, 136, 138, 140, or 142; and (b) one or moreamino acid differences relative to SEQ ID NO: 2 selected from: X37E;X277I; X278A or X278G; X280T or X280Y; X281I; X326R; and X490L or X490Q.In some embodiments, an engineered CHMO of the present disclosure caninclude the following amino acid differences relative SEQ ID NO: 2:X37E; X277I; X278A or X278G; X280T or X280Y; X281I; X326R; X433G; X435A;and X490L or X490Q.

In some embodiments, the present disclosure provides an engineeredpolypeptide having CHMO activity in which the amino acid sequence of thepolypeptide has (a) at least 96%, 97%, 98%, or 99% identity to SEQ IDNO: 38; and (b) one or more amino acid differences relative to SEQ IDNO: 2 selected from: X37E; X277I; X278A or X278G; X280T or X280Y; X281I;X326R; and X490L or X490Q.

In some embodiments, the present disclosure provides an engineeredpolypeptide having CHMO activity in which the amino acid sequence of thepolypeptide has (a) at least 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or99% identity to SEQ ID NO: 136; and (b) one or more amino aciddifferences relative to SEQ ID NO: 2 selected from: X37E; X277I; X278Aor X278G; X280T or X280Y; X281I; X326R; and X490L or X490Q.

As shown in Tables 2A and 2B, combinations of amino acid differencespresent in the exemplary polypeptides are associated with improvedproperties in converting compound (1a) to compound (2a) relative to thewild-type polypeptide of SEQ ID NO: 2 or another reference polypeptide,such as the engineered polypeptide of SEQ ID NO: 4 or 38. Accordingly,in some embodiments the amino acid sequence of any of the engineeredpolypeptides having CHMO activity of the present disclosure can compriseor further comprise at least one combination of amino acid differencesrelative to SEQ ID NO: 2 selected from the following:

-   -   (a) X37E, X277I, X278G, X280T, X281I, X326R, X432S, X433G,        X435A, and X490L;    -   (b) X3T, X143G, X280Y, X432S, X433G, X435A, and X532P;    -   (c) X3T, X75M, X143G, X280Y, X432S, X433G, X435A, and X532P;    -   (d) X3T, X75M, X143G, X280Y, X426S, X432S, X433G, X435A, X503A,        and X532P;    -   (e) X3T, X43G, X75M, X143G, X280Y, X426S, X432S, X433G, X435A,        X503A, X512N, and X532P;    -   (f) X3T, X43G, X75M, X143G, X280Y, X426S, X432S, X433G, X435A,        X491V, X503A, X504I, X512N, and X532P; or    -   (g) X3T, X43G, X75M, X143G, X166A, X280Y, X395R, X412L, X426S,        X432S, X433G, X435A, X491V, X503A, X504I, X512N, and X532P.

As shown in Tables 2A and 2B, combinations of amino acid differencespresent in the exemplary polypeptides are associated with improvedproperties in converting compound (1b) to compound (2b) relative to thewild-type polypeptide of SEQ ID NO: 2 or another reference polypeptide,such as the engineered polypeptide of SEQ ID NO: 4 or 38. Accordingly,in some embodiments the amino acid sequence of any of the engineeredpolypeptides having CHMO activity of the present disclosure can compriseor further comprise at least one combination of amino acid differencesrelative to SEQ ID NO: 2 selected from the following:

-   -   (a) X3T, X43G, X75M, X143G, X166A, X280Y, X395R, X412L, X426S,        X432S, X433G, X435A, X491V, X503A, X504I, X512N, and X532P;    -   (b) X3T, X43G, X75M, X99V, X143G, X161D, X166A, X174I, X273S,        X280Y, X324K, X395R, X412L, X426S, X432S, X433G, X435A, X491V,        X503A, X504I, X512N, and X532P;    -   (c) X3T, X43G, X75M, X79T, X82A, X99V, X110M, X143G, X161D,        X166A, X174I, X208T, X273S, X280Y, X324K, X395R, X412L, X426S,        X432S, X433G, X435A, X491V, X503A, X504I, X505K, X512N, and        X532P;    -   (d) X3T, X43G, X75M, X79T, X82A, X99V, X110M, X143G, X161D,        X166A, X174I, X208T, X273S, X280Y, X324K, X395R, X412L, X426S,        X432S, X433G, X435A, X472I, X486E, X491V, X503A, X504I, X505K,        X512N, and X532P;    -   (e) X3T, X43G, X75M, X79T, X82A, X99V, X110M, X143G, X161D,        X166A, X174I, X208T, X234D, X273S, X280Y, X324K, X395R, X412L,        X426S, X432S, X433G, X435A, X438M, X472I, X486E, X490Q, X491V,        X503A, X504I, X505K, X512N, and X532P;    -   (f) X3T, X43G, X75M, X79T, X82A, X99V, X110M, X143G, X161D,        X166A, X174I, X208T, X273S, X280Y, X324K, X395R, X412L, X426S,        X432S, X433G, X435A, X438M, X472I, X484C, X486E, X490Q, X491V,        X503A, X504I, X505K, X512N, and X532P;    -   (g) X3T, X43G, X75M, X79T, X82A, X99V, X110M, X143G, X161D,        X166A, X172A, X174I, X208T, X243K, A245G, X273S, X280Y, X319T,        X324K, X325Y, X395R, X412L, X426S, X432S, X433G, X435A, X438M,        X472I, X484C, X486E, X490Q, X491V, X492K, X501D, X503A, X504I,        X505K, X512N, and X532P;    -   (h) X3T, X43G, X62V, X75M, X79T, X82A, X99V, X110M, X143G,        X161D, X166A, X174I, X208T, X273S, X275S, X280Y, X324K, X329V,        X395R, X412L, X426S, X432S, X433G, X435A, X438M, X472I, X484C,        X486E, X490Q, X491V, X503A, X504I, X505K, X512N, and X532P;    -   (i) X3T, X43G, X75M, X79T, X82A, X99V, X110M, X118V, X143G,        X161D, X166A, X172A, X174I, X208T, X216I, X264Y, X273S, X280Y,        X291R, X310H, X319T, X324K, X325Y, X395R, X412L, X426S, X432S,        X433G, X435A, X438M, X472I, X484C, X486E, X490Q, X491V, X492K,        X501D, X503A, X504I, X505K, X512N, and X532P;    -   (j) X3T, X43G, X75M, X79T, X82A, X89N, X99V, X110M, X118V,        X143S, X161D, X166A, X172A, X174I, X208T, X216I, X219V, X264Y,        X273S, X275A, X280Y, X291R, X310H, X319T, X324K, X325Y, X362S,        X395R, X412L, X426S, X432S, X433G, X435A, X438M, X472I, X484C,        X486E, X490Q, X491V, X492K, X501D, X503A, X504I, X505K, X512N,        and X532P; or    -   (k) X3T, X43G, X75M, X79T, X82A, X84H, X89N, X99V, X110M, X118V,        X143S, X161D, X166A, X172A, X174I, X208T, X216I, X219V, X264Y,        X273S, X275A, X280Y, X291R, X310H, X319T, X324K, X325Y, X362S,        X395R, X412L, X426S, X432S, X433G, X435A, X438M, X472I, X473D,        X477D, X484L, X486E, X490Q, X491V, X492K, X498N, X501D, X503A,        X504I, X505K, X512N, and X532P.

In some embodiments, the present disclosure provides a non-naturallyoccurring polypeptide having CHMO activity capable of convertingcompound (1a) to compound (2a), and/or compound (1b) to compound (2b),with at least 2-fold, at least 10-fold, at least 25-fold, at least40-fold, or at least 60-fold increased enzyme activity relative to theenzyme activity of the polypeptide of SEQ ID NO: 2. The non-naturallyoccurring polypeptide comprises an amino acid sequence having at least80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%,98%, or 99% identity to a reference amino acid sequence SEQ ID NO: 2 andthe following amino acid differences relative to SEQ ID NO: 2: X37E,X277I, X278G, X281I, X326R, X433G, and X435A. The amino acid sequencemay further comprise X3T, X143G, X280Y, or a combination thereof. Theamino acid sequence may further comprise X75M. The amino acid sequencemay further comprise X426S, X503A, or a combination thereof. The aminoacid sequence may further comprise X43G, X512N, or a combinationthereof. The amino acid sequence may further comprise X491V, X504I, or acombination thereof. The amino acid sequence may further comprise X166A,X395R, X412L, or a combination thereof. The amino acid sequence mayfurther comprise X99V, X161D, X174I, X273S, X324K, or a combinationthereof. The amino acid sequence may further comprise X79T, X82A, X110M,X208T, X216S, X505K, or a combination thereof. The amino acid sequencemay further comprise X472I, X486E, or a combination thereof. The aminoacid sequence can further comprise X438M, X490Q, or a combinationthereof. The amino acid sequence may further comprise X484C. The aminoacid sequence can further comprise X62V, X275N, X329V, or a combinationthereof; wherein X refers to a position relative to SEQ ID NO: 2.

As shown by the exemplary polypeptides disclosed in Tables 2A, 2B, and2C, the engineered polypeptides having CHMO activity also have improvedproperties that correlate with the amino acid differences relative toSEQ ID NO: 2. Accordingly, in some embodiments, the non-naturallyoccurring polypeptides having CHMO activity described herein are capableof converting compound (1a) to compound (2a) and/or compound (1b) tocompound (2b) in at least 75%, at least 85%, at least 90%, at least 95%,at least 98%, or at least 99% enantiomeric excess under suitablereaction conditions. In some embodiments, the non-naturally occurringCHMO polypeptides described herein are capable of converting compound(1a) to compound (2a) with an activity increased at least 2-fold, atleast 4-fold, at least 10-fold, at least 25-fold, at least 40-fold, orat least 60-fold relative to the activity of the polypeptide of SEQ IDNO: 2 under suitable reaction conditions. In some embodiments, thenon-naturally occurring CHMO polypeptides described herein are capableof converting compound (1b) to compound (2b) with an activity increasedat least 2-fold, at least 4-fold, at least 10-fold, at least 25-fold, atleast 40-fold, or at least 60-fold relative to the activity of thepolypeptide of SEQ ID NO: 38 under suitable reaction conditions. In someembodiments, the non-naturally occurring CHMO polypeptides describedabove are capable of at least about 90% or greater conversion ofcompound (1b) to compound (2b) in 24 h with a substrate loading of about50 g/L. As described elsewhere herein, the improved properties of thenon-naturally occurring or engineered CHMO polypeptides provide formethods of use of these polypeptides in processes for preparingArmodafinil (compound (2a)) and analogs thereof.

Analysis of the relationship between the structural changes (i e, aminoacid differences) and improved properties of the exemplary polypeptidesof Tables 2A, 2B, and 2C, further allows for the identification ofspecific amino acid differences that are associated with one or moreimproved properties including increased enantiomeric excess, increasedactivity, increased thermostability, and/or increased tolerance of highsubstrate and/or product concentration.

In some embodiments, the present disclosure provides a non-naturallyoccurring polypeptide having CHMO activity capable of converting theamide substrate of compound (1a) to compound (2a) with at least 2-fold,at least 10-fold, at least 25-fold, at least 40-fold, or at least60-fold increased enzyme activity relative to the enzyme activity of thepolypeptide of SEQ ID NO: 2 and in which the polypeptide amino acidsequence comprises one or more amino acid differences relative to SEQ IDNO: 2 associated with increased activity in converting compound (1a) tocompound (2a). Accordingly, in some embodiments the present disclosureprovides a non-naturally occurring polypeptide comprises (a) an aminoacid sequence having at least 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%,92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to a reference aminoacid sequence selected from any one of SEQ ID NO: 2, 4, 6, 8, 10, 12,14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48,50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84,86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116,118, 120, 122, 124, 126, 128, 130, 132, 134, 136, 138, 140, and 142; and(b) at least one of the following amino acid differences relative to SEQID NO: 2 which are associated with increased activity in convertingcompound (1a) to compound (2a): Q3T; V42I; A43G; L75M; L143G; H163L orY; S166A or G; D171G; G176S; R278G; M280Y; F281I; A288L or V; A313E;D322G or M; K326R; V348A; E364K; A382R; K395R; M412L; L426N or S; G430R;L435A; N477D; S489G; F492K or S; V503A; Y504I; E512N; L532P; and K538E.

In some embodiments, the present disclosure provides a non-naturallyoccurring polypeptide having CHMO activity which is capable ofconverting the acid substrate of compound (1b) to compound (2b) with atleast 2-fold, at least 10-fold, at least 25-fold, at least 40-fold, orat least 60-fold increased enzyme activity relative to the enzymeactivity of the polypeptide of SEQ ID NO: 2 and in which the polypeptideamino acid sequence comprises one or more amino acid differencesrelative to SEQ ID NO: 2 associated with increased activity inconverting compound (1b) to compound (2b). Accordingly, in someembodiments the present disclosure provides a non-naturally occurringpolypeptide comprises (a) an amino acid sequence having at least 80%,85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or99% identity to a reference amino acid sequence selected from any one ofSEQ ID NO: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32,34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68,70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102,104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130,132, 134, 136, 138, 140, and 142; and (b) at least one of the followingamino acid differences relative to SEQ ID NO: 2 which are associatedwith increased activity in converting compound (1b) to compound (2b):V42I; A43G; K79T; V82A or I; K89M or N; V110M; E123A; L143G or S; H163Lor Y; S166A or G; V172A; G176S; I182V; I192V; 5208T; G216I; K227D or E;A243K; A245G; T273A, C, or S; G275A; R278G; A288L or V; N290D; M291R;I314L or T; M319L or T; D322G or M; Y324K; A325Y; K326R; L329V; V348A;E364K; M373V; A382R; K395R; M412L; L426N or S; G430R; F432S; L435A;S438M or R; T472I; N477D; I478L; F484C; K486E; S489G; W490Q; I491V;F492K or S; N501D; V503A; F505K; E512N; K538E and Q539E.

In some embodiments, the present disclosure provides a non-naturallyoccurring polypeptide having CHMO activity which is capable ofconverting the acid substrate of compound (1a) to compound (2a) with atleast 75%, or at least 80%, or at least 85%, or at least 90%, or atleast 95%, or at least 97%, or at least 98%, of the enantiomeric excess(e.e.) and in which the polypeptide amino acid sequence comprises one ormore amino acid differences relative to SEQ ID NO: 2 associated withincreased enantioselectivity in converting compound (1a) to compound(2a). Accordingly, in some embodiments the present disclosure provides anon-naturally occurring polypeptide comprises non-naturally occurringpolypeptide comprises (a) an amino acid sequence having at least 80%,85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or99% identity to a reference amino acid sequence selected from any one ofSEQ ID NO: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32,34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68,70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102,104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130,132, 134, 136, 138, 140, and 142; and (b) at least one of the followingamino acid differences relative to SEQ ID NO: 2 associated withincreased enantioselectivity in converting compound (1a) to compound(2a): M280Y, L426N, L426S, G430R, L435A, and L532P.

In some embodiments, the present disclosure provides a non-naturallyoccurring polypeptide having CHMO activity which is capable ofconverting compound (1b) (acid substrate) to compound (2b) with at least75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%,or at least 97%, or at least 98%, of the enantiomeric excess (e.e.) andin which the polypeptide amino acid sequence comprises one or more aminoacid differences relative to SEQ ID NO: 2 associated with increasedenantioselectivity in converting compound (1b) to compound (2b).Accordingly, in some embodiments the present disclosure provides anon-naturally occurring polypeptide comprises (a) an amino acid sequencehaving at least 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%,95%, 96%, 97%, 98%, or 99% identity to a reference amino acid sequenceselected from any one of SEQ ID NO: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20,22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56,58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92,94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122,124, 126, 128, 130, 132, 134, 136, 138, 140, and 142; and (b) at leastone of the following amino acid differences relative to SEQ ID NO: 2associated with increased enantioselectivity in converting compound (1b)to compound (2b): V110M; D322G, D322M, A325Y, G430R, F432S, and F505K.

In some embodiments, the non-naturally occurring polypeptides havingCHMO activity also have increased thermostability as compared to thepolypeptide of SEQ ID NO: 2 associated with certain amino aciddifferences relative to SEQ ID NO: 2. Increased thermostability can bedetermined by preincubating the polypeptide at a defined temperature andtime, e.g., 4° C.-46° C. for 18-24 hours, followed by measuring the %residual activity using a defined assay. Exemplary preincubationconditions include preincubation at 30° C. for 18 h, or 40° C. for 24 h.Accordingly, in some embodiments, specific amino acid differencesresulting in increased thermostability by having at least 1.5-fold,2.5-fold, 5-fold, 7.5-fold, or more, relative to the referencepolypeptide of SEQ ID NO: 2; those amino acid differences can beselected from the following substitutions: A43G; S166A or G; G216I;K264Y; M291R; Y324K; E364K; K395R; M412L; N477D; and E512N. Accordingly,in some embodiments the present disclosure provides a non-naturallyoccurring polypeptide having CHMO activity which also has at least1.5-fold, 2.5-fold, 5-fold, 7.5-fold, or more increased thermostabilityrelative to the reference polypeptide of SEQ ID NO: 2 and whichcomprises (a) an amino acid sequence having at least 80%, 85%, 86%, 87%,88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identityto a reference amino acid sequence selected from any one of SEQ ID NO:2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38,40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74,76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108,110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 132, 134, 136,138, 140, and 142; and (b) at least one of the following amino aciddifferences relative to SEQ ID NO: 2 associated with increasedthermostability: A43G; S166A or G; G216I; K264Y; M291R; Y324K; E364K;K395R; M412L; N477D; and E512N.

In some embodiments, the non-naturally occurring polypeptides havingCHMO activity which are capable of converting compound (1b) to compound(2b) have an increased tolerance of the presence of substrate ofcompound (1b) and/or the presence of the product of compound (2b) ascompared to the polypeptide of SEQ ID NO: 2 associated with thefollowing amino acid differences relative to SEQ ID NO: 2: K89N, L143S,G216I, A243K, A245G, G275A, and A325Y. Accordingly, in some embodimentsthe present disclosure provides a non-naturally occurring polypeptidehaving CHMO activity which is capable of converting at least 90% ofcompound (1b) at a concentration of at least 30 g/L, at least 50 g/L, atleast 60 g/L, at least 70 g/L, at least 80 g/L, at least 90 g/L, or atleast 100 g/L of to compound (2b) in 24 h under suitable reactionconditions, and which comprises (a) an amino acid sequence having atleast 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%,97%, 98%, or 99% identity to a reference amino acid sequence selectedfrom any one of SEQ ID NO: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24,26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60,62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96,98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124,126, 128, 130, 132, 134, 136, 138, 140, and 142; and (b) at least one ofthe following amino acid differences relative to SEQ ID NO: 2 associatedwith increased substrate and/or product tolerance: K89N, L143S, G216I,A243K, A245G, G275A, and A325Y.

In some embodiments of the non-naturally occurring polypeptides havingCHMO activity described herein, the amino acid sequence furthercomprises an amino acid difference relative to SEQ ID NO: 2 at one ormore positions selected from the following: X3, X32, X40, X42, X43, X54,X62, X74, X75, X79, X82, X84, X89, X99, X110, X118, X123, X135, X143,X161, X163, X166, X171, X172, X174, X176, X182, X192, X208, X216, X219,X227, X234, X243, X245, X264, X273, X275, X288, X290, X291, X310, X313,X314, X319, X322, X324, X325, X329, X336, X348, X362, X364, X373, X382,X395, X412, X426, X430, X438, X472, X473, X477, X478, X484, X486, X489,X491, X492, X498, X501, X503, X504, X505, X512, X532, X538, and X539.

In some embodiments of the non-naturally occurring polypeptides havingCHMO activity described above, the amino acid sequence further comprisesan amino acid difference relative to SEQ ID NO: 2 selected from thefollowing: X3T, X32E, X40G, X42I, X43G, X54V, X62V, X74E, X75M, X79T,X82A, X82I, X84H, X89M, X89N, X99V, X110M, X118V, X123A, X135K, X143G,X143S, X161D, X163L, X163Y, X166A, X166G, X171G, X172A, X172M, X174I,X176S, X182V, X192V, X208T, X216I, X216S, X219V, X227D, X227E, X234D,X243K, X245G, X264Y, X273A, X273C, X273S, X275A, X275N, X275S, X288L,X288V, X290D, X291R, X310E, X310H, X313E, X314L, X314T, X319L, X319T,X322G, X322M, X324K, X325F, X325Y, X329V, X336S, X348A, X362S, X364K,X373V, X382R, X395R, X412L, X426N, X426S, X430R, X438M, X438R, X472I,X473D, X477D, X478L, X484C, X484L, X486E, X489G, X491V, X492K, X492S,X498N, X501D, X503A, X504I, X505K, X512N, X532P, X538E, and X539E.

Based on modeling studies of the wild-type CHMO of Acinetobacter spNCIMB9871 of SEQ ID NO:2, at least the following residue positions arewithin 8A of the FAD prosthetic group on the enzyme: X14, X34, X43;X111, X141, X386, X388, X426, X432, X433, X435, and X438; at least thefollowing residue positions are within 8A of enzyme-bound NADPH cofactorX149, X209, X277, X326, X426, X432, X435, X438, X488, X489, and X490;and at least the following residue positions are within 8A ofenzyme-bound substrate X277, X326, X426, X432, X433, X435, X438, X489,X490, and X505. While these residue positions are in close proximity tobound substrate, FAD prosthetic group, and co-factor, it has been foundthat the amino acid residues at these residue positions as well asothers disclosed herein can be varied to alter specific enzymeproperties, including, among others, substrate binding, enzyme activity,and enantioselectivity. In some embodiments, the present disclosure alsocontemplates a non-naturally occurring polypeptide having CHMO activitywhich are capable of converting compound (1a) to compound (2a), orcompound (1b) to compound (2b), with improved properties relative to theactivity of the polypeptide of SEQ ID NO: 2, wherein the non-naturallyoccurring polypeptide comprises an amino acid sequence having at least80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%,98%, or 99% identity to SEQ ID NO: 2, and further comprises a set ofamino acid residue differences as compared to SEQ ID NO:2, wherein theamino acid differences are based on locations or regions in thestructure of reference polypeptide (e.g., SEQ ID NO: 2) and/or theassociated functional properties. Accordingly, referring to Table 3, anon-naturally occurring or engineered polypeptide having CHMO activityof the present disclosure can include an amino acid substitution at aparticular residue at a location in the structure of the referencepolypeptide as identified in Table 3. Exemplary substitutions at each ofthe relevant locations include those identified in Tables 2A, 2B, and2C.

TABLE 3 Structural Locations Useful for Engineered CHMO PolypeptidesCorresponding Position in SEQ ID NO: 2 Structural Location X3 SurfaceX14 Buried-close to FAD X15 Buried-FAD-binding X22 Buried (non activesite) X32 Surface X34 Surface X37 Partially Buried-FAD-Binding X39Partially Buried (FAD-Binding site) X40 Surface X42 Partially Buried(non-active site) X43 Partially Buried-Near FAD X44 Buried-FAD-BindingX54 Partially Buried X59 Surface (near active site) X62 Surface X71Partially Buried (non-active site) X74 Surface X75 Buried X79 SurfaceX82 Partially Buried (non-active site) X83 Surface X84 Surface X89Surface X92 Surface X99 Surface X103 Surface X107 Surface X110 Buried(close to FAD) X111 Surface X113 Buried (non active site) X114 SurfaceX118 Surface X123 Surface X135 Surface X141 Buried-FAD-Binding X143Active Site X144 Active Site X145 FAD-Binding X146 Partially Buried X149Surface X154 Surface X155 Surface X161 Surface X163 Surface X166Partially Buried (close to FAD) X171 Surface X172 Surface X174 Buried(non active site) X176 Surface X182 Interacts with NADP X192 Buried X194Surface X195 Buried (non active site) X199 Buried (non active site) X201Surface X208 Surface-close to NADP X209 Surface-close to NADP X216Surface X219 Surface X227 Surface X234 Surface X240 Surface X243 SurfaceX244 Active Site X245 Active Site X246 Active Site X248 Surface X264Surface X273 Surface X275 Partially Buried (active site) X277 ActiveSite X278 Surface X280 Partially Buried (active site) X281 Surface X288Surface X290 Surface X291 Surface X301 Buried X307 Surface X310 SurfaceX313 Surface X314 Buried X319 Surface X322 Surface X324 Buried X325Partially Buried (non-active site) X326 Partially Buried (Active Site)X329 Buried (active site main chain) X330 Buried (active site mainchain) X336 Surface X341 Surface X348 Partially Buried (non-active site)X354 Surface X362 Surface X364 Partially Buried (non-active site) X367Surface X368 Surface X373 Partially Buried (non-active site) X382 Buried(Active Site) X383 Active Site X386 Surface (FAD-Binding site) X388Surface X390 Buried-FAD-Binding X395 Surface X400 Buried (non-activesite) X408 Partially Buried (non active site) X412 Partially Buried(non-active site) X415 Buried (non active site) X426 Active Site X428Buried (active site main chain) X430 Active Site X432 Active Site X433Active Site X435 Active Site X438 Active Site X448 Surface X449 SurfaceX451 Buried (non active site) X454 Surface X459 Surface X472 SurfaceX473 Surface X475 Buried (non active site) X477 Surface X478 SurfaceX481 Surface X484 Active Site X486 Surface X487 Active Site X488 SurfaceX489 Partially Buried-Active Site X490 Active Site X491 Active Site X492Surface (Active Site) X498 Surface X499 Surface X501 Surface X503Surface X504 Active Site X505 Active Site X507 Partially Buried (nearactive site) X512 Surface X516 Surface X526 Surface X532 Surface X537Surface X538 Surface X539 Surface X540 Surface

As will be apparent to the skilled artisan, various combinations ofresidue differences as compared to SEQ ID NO: 2 at residue positionsaffecting enzymatic activity, thermostability, can be made to form theengineered polypeptides having CHMO activity of the present disclosure.

In addition to the residue positions specified above, any of thenon-naturally occurring polypeptides having CHMO activity disclosedherein can further comprise other residue differences relative to SEQ IDNO: 2 at other residue positions. Residue differences at these otherresidue positions provide for additional variations in the amino acidsequence without adversely affecting the CHMO activity of thepolypeptide, including the ability to carry out the conversion ofcompound (1a) to compound (2a), or compound (1b) to compound (2b). Insome embodiments, the polypeptides can have additionally 1-2, 1-3, 1-4,1-5, 1-6, 1-7, 1-8, 1-9, 1-10, 1-11, 1-12, 1-14, 1-15, 1-16, 1-18, 1-20,1-22, 1-24, 1-26, 1-30, 1-35, 1-40 residue differences at other aminoacid residue positions as compared to the reference sequence. In someembodiments, the number of differences can be 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 14, 15, 16, 18, 20, 22, 24, 26, 30, 35, and 40 residuedifferences at other residue positions. The residue difference at theseother positions can include conservative changes or non-conservativechanges. In some embodiments, the residue differences can compriseconservative substitutions and non-conservative substitutions ascompared to the wild-type CHMO of SEQ ID NO: 2. In some embodiments,these engineered polypeptides having CHMO activity are capable ofconverting compound (1a) to compound (2a) and/or compound (1b) tocompound (2b) under suitable reaction conditions with improvedproperties relative to the naturally occurring CHMO polypeptide of SEQID NO: 2.

Amino acid residue differences at other positions relative the wild-typeCHMO amino acid sequence of SEQ ID NO: 2 and the affect of thesedifferences on enzyme function are provide by the engineered CHMOpolypeptides disclosed U.S. provisional patent application 61/267,812,filed Dec. 8, 2009, which is hereby incorporated by reference herein.Accordingly, in some embodiments, it is contemplated that one or more ofthe amino acid differences relative to SEQ ID NO: 2 disclosed in theengineered CHMO polypeptides of this US provisional patent applicationcould also be introduced into a non-naturally occurring CHMO polypeptideof the present disclosure, including any one or more of the following:X14A; X34K; X71M; X111T; X1411; X141V; X149W; X149V; X174L; X209P;X240K; X246Y; X246W; X248C; X248N; X248V; X248S; X288I; X307R; X326T;X326C; X329N; X383I; X388K; X390R; X390I; X400I; X415A; X426F; X432A;X432L; X433A; X435S; X438I; X448V; X448W; X449M; X449F; X449L; X451R;X481K; X488K; X489C; X490R X499L; X505W; X505L; X516V; X526V; X537T;X540Q; and X540A. In some embodiments, the present disclosure providesengineered polypeptides having CHMO activity which have an amino acidsequence that comprises (a) an amino acid sequence having at least 80%,85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or99% identity to a reference amino acid sequence selected from any one ofSEQ ID NO: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32,34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68,70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102,104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130,132, 134, 136, 138, 140, and 142; and (b) one or more of the followingamino acid differences as compared to SEQ ID NO:2: X14A; X34K; X71M;X111T; X1411; X141V; X149W; X149V; X174L; X209P; X240K; X246Y; X246W;X248C; X248N; X248V; X248S; X288I; X307R; X326T; X326C; X329N; X383I;X388K; X390R; X390I; X400I; X415A; X426F; X432A; X432L; X433A; X435S;X438I; X448V; X448W; X449M; X449F; X449L; X451R; X481K; X488K; X489C;X490R X499L; X505W; X505L; X516V; X526V; X537T; X540Q; and X540A. Insome embodiments, these engineered polypeptides having CHMO activity arecapable of converting compound (1a) to compound (2a) and/or compound(1b) to compound (2b) under suitable reaction conditions with improvedproperties relative to the naturally occurring CHMO polypeptide of SEQID NO: 2.

Alternatively, in some embodiments the present disclosure provides anengineered polypeptide having CHMO activity wherein the amino acidsequence excludes one or more of the amino acid differences relative toSEQ ID NO: 2 disclosed in U.S. provisional patent application61/267,812, filed Dec. 8, 2009. Accordingly, in some embodiments, thepresent disclosure provides engineered polypeptides having CHMO activitywhich have an amino acid sequence that (a) comprises an amino acidsequence having at least 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%,93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to a reference amino acidsequence selected from any one of SEQ ID NO: 2, 4, 6, 8, 10, 12, 14, 16,18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52,54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88,90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118,120, 122, 124, 126, 128, 130, 132, 134, 136, 138, 140, and 142; and (b)does not include one or more of the following amino acid differences ascompared to SEQ ID NO:2: X14A; X34K; X71M; X111T; X1411; X141V; X149W;X149V; X174L; X209P; X240K; X246Y; X246W; X248C; X248N; X248V; X248S;X288I; X307R; X326T; X326C; X329N; X383I; X388K; X390R; X390I; X400I;X415A; X426F; X432A; X432L; X433A; X435S; X438I; X448V; X448W; X449M;X449F; X449L; X451R; X481K; X488K; X489C; X490R X499L; X505W; X505L;X516V; X526V; X537T; X540Q; and X540A. In some embodiments, theseengineered polypeptides having CHMO activity are capable of convertingcompound (1a) to compound (2a) and/or compound (1b) to compound (2b)under suitable reaction conditions with improved properties relative tothe naturally occurring CHMO polypeptide of SEQ ID NO: 2.

In some embodiments, the present disclosure provides engineeredpolypeptides having CHMO activity which have an amino acid sequence thatcomprises (a) an amino acid sequence having at least 80%, 85%, 86%, 87%,88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identityto a reference amino acid sequence selected from any one of SEQ ID NO:2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38,40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74,76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108,110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 132, 134, 136,138, 140, and 142; and (b) specifically excludes one or more of thefollowing amino acid differences or sets of amino acid differences ascompared to SEQ ID NO:2: D41N and F505Y; K78E and F432S; L143F; L220Q,P428S and T433A; F432S; F432I; L426P and A541V; F432Y and K500R; andL143F, E292G, L435Q, and T464A; D384H; K229I and L248P; Y132C, F246I,V361A, and T415A; and F16L and F277S. These excluded amino aciddifferences are disclosed in Mihovilovic et al., 2006, Organic Lett.8(6):1221-1224; Reetz et al., 2004, Angew. Chem. Int. Ed. 43:4075-4078;Reetz et al., 2004, Angew Chem. Int. Ed. 43:4078-4081; the disclosuresof which are incorporated herein by reference. In some embodiments,these engineered polypeptides having CHMO activity are capable ofconverting compound (1a) to compound (2a) and/or compound (1b) tocompound (2b) under suitable reaction conditions with improvedproperties relative to the naturally occurring CHMO polypeptide of SEQID NO: 2.

In some embodiments, the present disclosure provides engineeredpolypeptides having CHMO activity which have an amino acid sequence thatcomprises (a) an amino acid sequence having at least 80%, 85%, 86%, 87%,88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identityto a reference amino acid sequence selected from any one of SEQ ID NO:2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38,40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74,76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108,110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 132, 134, 136,138, 140, and 142; and (b) specifically excludes the following wild-typeamino acid sequences (identified by UniProt databank accession numbers):(i) gi|81324523|sp|Q9F7E4|Q9F7E4_9 GAMM Cyclohexanone monooxygenase;(ii) gi|118066|sp|P12015.21CYMO_ACISP RecName: Full=Cyclohexanone1,2-monooxygenase; (iii) gi|123163966|sp|Q11Z78|Q11Z78_POLSJFlavin-containing monooxygenase FMO; (iv) tr|A3U3H1|A3U3H1_9 RHOBFlavin-containing monooxygenase FMO:FAD dependent oxidoreductaseOS═Oceanicola batsensis HTCC2597 GN=OB2597_18631 PE=4 SV=1; (v)tr|A3T2M3|A3T2M3_9 RHOB Flavin-containing monooxygenase FMO:FADdependent oxidoreductase OS═Sulfitobacter sp. NAS-14.1 GN=NAS141_04678PE=4 SV=1; and (vi) tr|A1W7Q2|A1W7Q2_ACISJ Cyclohexanone monooxygenaseOS=Acidovorax sp. (strain JS42) GN=Ajs_2102 PE=4 SV=1. In someembodiments, these engineered polypeptides having CHMO activity arecapable of converting compound (1a) to compound (2a) and/or compound(1b) to compound (2b) under suitable reaction conditions with improvedproperties relative to the naturally occurring CHMO polypeptide of SEQID NO: 2.

In some embodiments, the polypeptides can comprise deletions of theengineered CHMO polypeptides described herein. Thus, for each and everyembodiment of the polypeptides of the disclosure, the deletions cancomprise one or more amino acids, 2 or more amino acids, 3 or more aminoacids, 4 or more amino acids, 5 or more amino acids, 6 or more aminoacids, 8 or more amino acids, 10 or more amino acids, 15 or more aminoacids, or 20 or more amino acids, up to 10% of the total number of aminoacids, up to 10% of the total number of amino acids, up to 20% of thetotal number of amino acids of the polypeptides, as long as thefunctional activity of the polypeptide with respect to the conversion ofcompound (1a) to compound (2a), or compound (1b) to compound (2b) ispresent. In some embodiments, the deletions can comprise, 1-2, 1-3, 1-4,1-5, 1-6, 1-7, 1-8, 1-9, 1-10, 1-11, 1-12, 1-14, 1-15, 1-16, 1-18, 1-20,1-22, 1-24, 1-26, 1-30, 1-35, or 1-40 amino acid residues. In someembodiments, the number of deletions can be 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 14, 15, 16, 18, 20, 22, 24, 26, 30, 35, or 40 amino acids.In some embodiments, the deletions can comprise deletions of 1, 2, 3, 4,5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, or 20 amino acidresidues.

In some embodiments, the polypeptides can comprise fragments of theengineered polypeptides described herein. In some embodiments, thefragments can have about 80%, 90%, 95%, 98%, and 99% of the full-lengthpolypeptide, as long as the functional activity of the polypeptide withrespect to the conversion of compound from compound (1a) to compound(2a), or compound (1b) to compound (2b) is present.

In some embodiments, the polypeptides of the disclosure can be in theform of fusion polypeptides in which the engineered polypeptides arefused to other polypeptides, such as, by way of example and notlimitation, antibody tags (e.g., myc epitope), purifications sequences(e.g., His tags for binding to metals), and cell localization signals(e.g., secretion signals). Thus, the engineered polypeptides describedherein can be used with or without fusions to other polypeptides.

As will be understood by the skilled artisan, the polypeptides describedherein are not restricted to the genetically encoded amino acids. Inaddition to the genetically encoded amino acids, the polypeptidesdescribed herein may be comprised, either in whole or in part, ofnaturally-occurring and/or synthetic non-encoded amino acids. Certaincommonly encountered non-encoded amino acids of which the polypeptidesdescribed herein may be comprised include, but are not limited to: theD-enantiomers of the genetically-encoded amino acids;2,3-diaminopropionic acid (Dpr); α-aminoisobutyric acid (Aib);ε-aminohexanoic acid (Aha); δ-aminovaleric acid (Ava); N-methylglycineor sarcosine (MeGly or Sar); ornithine (Orn); citrulline (Cit);t-butylalanine (Bua); t-butylglycine (Bug); N-methylisoleucine (MeIle);phenylglycine (Phg); cyclohexylalanine (Cha); norleucine (Nle);naphthylalanine (Nal); 2-chlorophenylalanine (Oct);3-chlorophenylalanine (Mcf); 4-chlorophenylalanine (Pcf);2-fluorophenylalanine (Off); 3-fluorophenylalanine (Mff);4-fluorophenylalanine (Pff); 2-bromophenylalanine (Obf);3-bromophenylalanine (Mbf); 4-bromophenylalanine (Pbf);2-methylphenylalanine (Omf); 3-methylphenylalanine (Mmf);4-methylphenylalanine (Pmf); 2-nitrophenylalanine (Onf);3-nitrophenylalanine (Mnf); 4-nitrophenylalanine (Pnf);2-cyanophenylalanine (Oct); 3-cyanophenylalanine (Mcf);4-cyanophenylalanine (Pcf); 2-trifluoromethylphenylalanine (Otf);3-trifluoromethylphenylalanine (Mtf); 4-trifluoromethylphenylalanine(Ptf); 4-aminophenylalanine (Paf); 4-iodophenylalanine (Pif);4-aminomethylphenylalanine (Pamf); 2,4-dichlorophenylalanine (Opef);3,4-dichlorophenylalanine (Mpcf); 2,4-difluorophenylalanine (Opff);3,4-difluorophenylalanine (Mpff); pyrid-2-ylalanine (2pAla);pyrid-3-ylalanine (3pAla); pyrid-4-ylalanine (4pAla); naphth-1-ylalanine(1nAla); naphth-2-ylalanine (2nAla); thiazolylalanine (taAla);benzothienylalanine (bAla); thienylalanine (tAla); furylalanine (fAla);homophenylalanine (hPhe); homotyrosine (hTyr); homotryptophan (hTrp);pentafluorophenylalanine (5ff); styrylkalanine (sAla); authrylalanine(aAla); 3,3-diphenylalanine (Dfa); 3-amino-5-phenypentanoic acid (Afp);penicillamine (Pen); 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid(Tic); β-2-thienylalanine (Thi); methionine sulfoxide (Mso);N(w)-nitroarginine (nArg); homolysine (hLys);phosphonomethylphenylalanine (pmPhe); phosphoserine (pSer);phosphothreonine (pThr); homoaspartic acid (hAsp); homoglutanic acid(hGlu); 1-aminocyclopent-(2 or 3)-ene-4 carboxylic acid; pipecolic acid(PA), azetidine-3-carboxylic acid (ACA);1-aminocyclopentane-3-carboxylic acid; allylglycine (aOly);propargylglycine (pgGly); homoalanine (hAla); norvaline (nVal);homoleucine (hLeu), homovaline (hVal); homoisolencine (hIle);homoarginine (hArg); N-acetyl lysine (AcLys); 2,4-diaminobutyric acid(Dbu); 2,3-diaminobutyric acid (Dab); N-methylvaline (MeVal);homocysteine (hCys); homoserine (hSer); hydroxyproline (Hyp) andhomoproline (hPro). Additional non-encoded amino acids of which thepolypeptides described herein may be comprised will be apparent to thoseof skill in the art (see, e.g., the various amino acids provided inFasman, 1989, CRC Practical Handbook of Biochemistry and MolecularBiology, CRC Press, Boca Raton, Fla., at pp. 3-70 and the referencescited therein, all of which are incorporated by reference). These aminoacids may be in either the L- or D-configuration.

Those skilled in the art will recognize that amino acids or residuesbearing side chain protecting groups may also comprise the polypeptidesdescribed herein. Non-limiting examples of such protected amino acids,which in this case belong to the aromatic category, include (protectinggroups listed in parentheses), but are not limited to: Arg(tos),Cys(methylbenzyl), Cys (nitropyridinesulfenyl), Glu(δ-benzylester),Gln(xanthyl), Asn(N-8-xanthyl), His(bom), His(benzyl), His(tos),Lys(fmoc), Lys(tos), Ser(O-benzyl), Thr (O-benzyl) and Tyr(O-benzyl).

Non-encoding amino acids that are conformationally constrained of whichthe polypeptides described herein may be composed include, but are notlimited to, N-methyl amino acids (L-configuration); 1-aminocyclopent-(2or 3)-ene-4-carboxylic acid; pipecolic acid; azetidine-3-carboxylicacid; homoproline (hPro); and 1-aminocyclopentane-3-carboxylic acid.

In some embodiments, the engineered polypeptides having CHMO activitydescribed herein can be provided in the form of kits. The enzymes in thekits may be present individually or as a plurality of enzymes. The kitscan further include reagents for carrying out the enzymatic reactions,substrates for assessing the activity of enzymes, as well as reagentsfor detecting the products. The kits can also include reagent dispensersand instructions for use of the kits.

In some embodiments, the engineered polypeptides having CHMO activity ofthe present disclosure can be provided on a substrate or otherwiseimmobilized on a solid support. “Substrate,” “support,” “solid support,”“solid carrier,” or “resin” in the context of refer to any solid phasematerial. Substrate also encompasses terms such as “solid phase,”“surface,” and/or “membrane.” A solid support can be composed of organicpolymers such as polystyrene, polyethylene, polypropylene,polyfluoroethylene, polyethyleneoxy, and polyacrylamide, as well asco-polymers and grafts thereof. A solid support can also be inorganic,such as glass, silica, controlled pore glass (CPG), reverse phase silicaor metal, such as gold or platinum. The configuration of a substrate canbe in the form of beads, spheres, particles, granules, a gel, a membraneor a surface. Surfaces can be planar, substantially planar, ornon-planar. Solid supports can be porous or non-porous, and can haveswelling or non-swelling characteristics. A solid support can beconfigured in the form of a well, depression, or other container,vessel, feature, or location.

In some embodiments, the engineered polypeptides having CHMO activity ofthe present disclosure can be immobilized on a solid support such thatthey retain their CHMO activity, improved activity relative to thepolypeptide of SEQ ID NO: 2, enantioselectivity, and/or other improvedproperties relative to the wild-type. In such embodiments, theimmobilized polypeptides can facilitate the biocatalytic conversionreactions of Scheme 1 or Scheme 2 (e.g., in processes for preparingarmodafinil as described herein), and after the reaction is complete areeasily retained (e.g., by retaining beads on which polypeptide isimmobilized) and then reused or recycled in subsequent reactions. Suchimmobilized enzyme processes allow for further efficiency and costreduction. Methods of enzyme immobilization are well-known in the art.

In some embodiments, the polypeptides can be provided in the form of anarray in which engineered polypeptides having different sequences areimmobilized in positionally distinct locations. Such arrays can be usedto test a variety of aryl alkyl sulfides for conversion by thepolypeptides. A plurality of supports can be configured on an array atvarious locations, addressable for robotic delivery of reagents, or bydetection methods and/or instruments.

In certain embodiments, the kits of the present disclosure includearrays comprising a plurality of different engineered polypeptideshaving CHMO activity at different addressable position, wherein thedifferent polypeptides are different variants of a reference sequenceeach having at least one different improved enzyme property. Such arrayscomprising a plurality of engineered polypeptides and methods of theiruse are described in, e.g., WO2009/008908A2.

1.3 CHMO Polynucleotides, Expression Vectors, and Host Cells

In another aspect, the present disclosure provides polynucleotidesencoding the non-naturally occurring or engineered polypeptidesdescribed herein. These polynucleotides may be operatively linked to oneor more heterologous regulatory sequences that control gene expressionto create a recombinant polynucleotide capable of expressing thepolypeptide having CHMO activity. Expression constructs containing aheterologous polynucleotide encoding the engineered polypeptide havingCHMO activity can be introduced into appropriate host cells to expressthe corresponding polypeptide.

Because of the knowledge of the codons corresponding to the variousamino acids, availability of a protein sequence provides a descriptionof all the polynucleotides capable of encoding the subject. Thus, havingidentified a particular amino acid sequence, those skilled in the artcould make any number of different nucleic acids by simply modifying thesequence of one or more codons in a way which does not change the aminoacid sequence of the protein. In this regard, the present disclosurespecifically contemplates each and every possible variation ofpolynucleotides that could be made by selecting combinations based onthe possible codon choices, and all such variations are to be consideredspecifically disclosed for any polypeptide disclosed herein, includingthe amino acid sequences presented in Tables 2A, 2B, and 2C.

In some embodiments, the polynucleotides can be selected and/orengineered to comprise codons that are preferably selected to fit thehost cell in which the protein is being produced. For example, preferredcodons used in bacteria are used to express the gene in bacteria;preferred codons used in yeast are used for expression in yeast; andpreferred codons used in mammals are used for expression in mammaliancells. Since not all codons need to be replaced to optimize the codonusage of the CHMO gene (e.g., because the natural sequence can havepreferred codons and because use of preferred codons may not be requiredfor all amino acid residues), codon optimized polynucleotides encodingthe CHMO polypeptides may contain preferred codons at about 40%, 50%,60%, 70%, 80%, or greater than 90% of codon positions of the full lengthcoding region.

In some embodiments, the polynucleotide encodes a non-naturallyoccurring polypeptide having CHMO activity and comprises an amino acidsequence having at least 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%,93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to a reference amino acidsequence selected from any one of SEQ ID NO: 4, 6, 8, 10, 12, 14, 16,18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52,54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88,90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118,120, 122, 124, 126, 128, 130, 132, 134, 136, 138, 140, and 142.

In some embodiments, the polynucleotide encodes a non-naturallyoccurring polypeptide having CHMO activity which is capable ofconverting compound (1a) to compound (2a), or compound (1b) to compound(2b) with at least 2-fold, at least 10-fold, at least 25-fold, at least40-fold, or at least 60-fold increased enzyme activity relative to theenzyme activity of the polypeptide of SEQ ID NO: 2, and comprises anamino acid sequence having at least 80%, 85%, 86%, 87%, 88%, 89%, 90%,91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to a referenceamino acid sequence selected from any one of SEQ ID NO: 4, 6, 8, 10, 12,14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48,50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84,86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116,118, 120, 122, 124, 126, 128, 130, 132, 134, 136, 138, 140, and 142,with the proviso that the amino acid sequence comprises any one of theset of residue differences as compared to SEQ ID NO: 2 contained in anyone of the polypeptide sequences of SEQ ID NO:4 to SEQ ID NO: 142 listedin Tables 2A and 2B.

In some embodiments, the polynucleotides encoding the polypeptideshaving CHMO activity are selected from SEQ ID NO: 3, 5, 7, 9, 11, 13,15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49,51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85,87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 117,119, 121, 123, 125, 127, 129, 131, 133, 135, 137, 139, and 141.

In some embodiments, the polynucleotides are capable of hybridizingunder highly stringent conditions to a polynucleotide comprising SEQ IDNO: 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37,39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73,75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107,109, 111, 113, 115, 117, 119, 121, 123, 125, 127, 129, 131, 133, 135,137, 139, 141, or a complement thereof, where the highly stringentlyhybridizing polynucleotides encode a non-naturally occurring polypeptidehaving CHMO activity. In some embodiments, the encoded polypeptide iscapable of converting compound (1a) to compound (2a), or compound (1b)to compound (2b), with at least 2-fold, at least 10-fold, at least25-fold, at least 40-fold, or at least 60-fold increased activityrelative to the activity of the polypeptide of SEQ ID NO: 2.

In some embodiments, the polynucleotides encode the polypeptides havingCHMO activity described herein but have about 80% or more sequenceidentity, about 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%,95%, 96%, 97%, 98%, or 99% or more sequence identity at the nucleotidelevel to a reference polynucleotide encoding the engineered CHMOpolypeptides described herein. In some embodiments, the polynucleotideis selected from SEQ ID NO: 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25,27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61,63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97,99, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 121, 123, 125,127, 129, 131, 133, 135, 137, 139, and 141.

An isolated polynucleotide encoding a non-naturally occurringpolypeptide having CHMO activity of the disclosure may be manipulated ina variety of ways to provide for expression of the polypeptide. In someembodiments, the polynucleotides encoding the polypeptides can beprovided as expression vectors where one or more control sequences ispresent to regulate the expression of the polynucleotides. Manipulationof the isolated polynucleotide prior to its insertion into a vector maybe desirable or necessary depending on the expression vector. Thetechniques for modifying polynucleotides and nucleic acid sequencesutilizing recombinant DNA methods are well known in the art. Guidance isprovided in Sambrook et al., 2001, Molecular Cloning: A LaboratoryManual, 3rd Ed., Cold Spring Harbor Laboratory Press; and CurrentProtocols in Molecular Biology, Ausubel. F. ed., Greene Pub. Associates,1998, updates to 2006.

In some embodiments, the control sequences include among others,promoters, leader sequence, polyadenylation sequence, propeptidesequence, signal peptide sequence, and transcription terminator.Suitable promoters can be selected based on the host cells used.Exemplary bacterial promoters include E. coli lac operon, E. coli trpoperon, bacteriophage □1, Streptomyces coelicolor agarase gene (dagA),Bacillus subtilis levansucrase gene (sacB), Bacillus licheniformisalpha-amylase gene (amyL), beta-lactamase gene, and tac promoter;exemplary promoters for filamentous fungal host cells, include promotersobtained from the genes for Aspergillus oryzae TAKA amylase, Rhizomucormiehei aspartic proteinase, Aspergillus niger neutral alpha-amylase,Aspergillus niger acid stable alpha-amylase, Aspergillus niger orAspergillus awamori glucoamylase (glaA), Rhizomucor miehei lipase,Aspergillus oryzae alkaline protease, Aspergillus oryzae triosephosphate isomerase, Aspergillus nidulans acetamidase, and Fusariumoxysporum trypsin-like protease, and mutant, truncated, and hybridpromoters thereof, and exemplary yeast cell promoters can be from thegenes for Saccharomyces cerevisiae enolase (ENO-1), Saccharomycescerevisiae galactokinase (GAL1), Saccharomyces cerevisiae alcoholdehydrogenase/glyceraldehyde-3-phosphate dehydrogenase (ADH2/GAP), andSaccharomyces cerevisiae 3-phosphoglycerate kinase.

In some embodiments, the control sequence may also be a signal peptidecoding region that codes for an amino acid sequence linked to the aminoterminus of a polypeptide and directs the encoded polypeptide into thecell's secretory pathway. The signal sequence typically depends on thetype of host cells being used to express the polypeptide. Effectivesignal peptide coding regions for bacterial host cells are the signalpeptide coding regions obtained from the genes for Bacillus NC1B 11837maltogenic amylase, Bacillus stearothermophilus alpha-amylase, Bacilluslichenifonnis subtilisin, Bacillus lichenifonnis beta-lactamase,Bacillus stearothermophilus neutral proteases (nprT, nprS, nprM), andBacillus subtilis prsA. Exemplary signal peptide coding regions forfilamentous fungal host cells can be the signal peptide coding regionsobtained from the genes for Aspergillus oryzae TAKA amylase, Aspergillusniger neutral amylase, Aspergillus niger glucoamylase, Rhizomucor mieheiaspartic proteinase, Humicola insolens cellulase, and Humicolalanuginosa lipase. Useful signal peptides for yeast host cells can befrom the genes for Saccharomyces cerevisiae alpha-factor andSaccharomyces cerevisiae invertase.

Other control sequences, such as leader sequence, polyadenylationsequence, and transcription terminator sequences can use those availablein the art (see Sambrook, supra, and Current Protocols in MolecularBiology, supra).

In another aspect, the present disclosure is also directed to arecombinant expression vector comprising a polynucleotide encoding anengineered polypeptide having CHMO activity or a variant thereof, andone or more expression regulating regions such as a promoter and aterminator, a replication origin, etc., depending on the type of hostsinto which they are to be introduced. The recombinant expression vectormay be any vector (e.g., a plasmid or virus), which can be convenientlysubjected to recombinant DNA procedures and can bring about theexpression of the polynucleotide sequence. The choice of the vector willtypically depend on the compatibility of the vector with the host cellinto which the vector is to be introduced. The vectors may be linear orclosed circular plasmids.

The expression vector may be an autonomously replicating vector, i.e., avector that exists as an extrachromosomal entity, the replication ofwhich is independent of chromosomal replication, e.g., a plasmid, anextrachromosomal element, a minichromosome, or an artificial chromosome.The vector may contain any means for assuring self-replication.Alternatively, the vector may be one which, when introduced into thehost cell, is integrated into the genome and replicated together withthe chromosome(s) into which it has been integrated. The expressionvector preferably contains one or more selectable markers, which permiteasy selection of transformed cells. A selectable marker is a gene theproduct of which provides for biocide or viral resistance, resistance toheavy metals, prototrophy to auxotrophs, resistance to chemical agents(e.g., antibiotics) and the like.

In another aspect, the present disclosure provides a host cellcomprising a polynucleotide encoding an engineered polypeptide havingCHMO activity of the present disclosure, the polynucleotide beingoperatively linked to one or more control sequences for expression ofthe CHMO polypeptide in the host cell. Host cells for use in expressingthe CHMO polypeptides encoded by the expression vectors of the presentdisclosure are well known in the art and include but are not limited to,bacterial cells, such as E. coli, Lactobacillus, Streptomyces andSalmonella typhimurium cells; fungal cells, such as yeast cells; insectcells such as Drosophila S2 and Spodoptera Sf9 cells; animal cells suchas CHO, COS, BHK, 293, and Bowes melanoma cells; and plant cells.Exemplary host cells are Escherichia coli BL21 and W3110.

Appropriate culture mediums and growth conditions for theabove-described host cells are well known in the art. Polynucleotidesfor expression of the CHMO may be introduced into host cells by variousmethods known in the art (e.g., electroporation, biolistic particlebombardment, liposome mediated transfection, calcium chloridetransfection, and protoplast fusion).

In the embodiments herein, the non-naturally occurring or engineeredCHMO polypeptides and nucleotides encoding such polypeptides can beprepared using methods commonly used by those skilled in the art. Insome embodiments, the parent polynucleotide sequence is codon optimizedto enhance expression of the CHMO in a specified host cell.

The engineered CHMO polypeptides can be obtained by subjecting thepolynucleotide encoding the naturally occurring CHMO to mutagenesisand/or directed evolution methods (see e.g., Stemmer, 1994, Proc NatlAcad Sci USA 91:10747-10751; PCT Publ. Nos. WO 95/22625, WO 97/0078, WO97/35966, WO 98/27230, WO 00/42651, and WO 01/75767; U.S. Pat. Nos.6,537,746, 6,117,679, 6,376,246, and 6,586,182; and U.S. Pat. Publ. Nos.20080220990A1 and 20090312196A1; each of which is hereby incorporated byreference herein).

Other directed evolution procedures that can be used include, amongothers, staggered extension process (StEP), in vitro recombination (Zhaoet al., 1998, Nat. Biotechnol. 16:258-261), mutagenic PCR (Caldwell etal., 1994, PCR Methods Appl. 3:S136-S140), and cassette mutagenesis(Black et al., 1996, Proc Natl Acad Sci USA 93:3525-3529). Mutagenesisand directed evolution techniques useful for the purposes herein arealso described in the following references: Ling, et al., 1997, Anal.Biochem. 254(2):157-78; Dale et al., 1996, Methods Mol. Biol. 57:369-74;Smith, 1985, Ann. Rev. Genet. 19:423-462; Botstein et al., 1985, Science229:1193-1201; Carter, 1986, “Site-directed mutagenesis,” Biochem. J.237:1-7; Kramer et al., 1984, Cell 38:879-887; Wells et al., 1985, Gene34:315-323; Minshull et al., 1999, Curr Opin Chem Biol 3:284-290;Christians et al., 1999, Nature Biotech 17:259-264; Crameri et al.,1998, Nature 391:288-291; Crameri et al., 1997, Nature Biotech15:436-438; Zhang et al., 1997, Proc Natl Acad Sci USA 94:45-4-4509;Crameri et al., 1996, Nature Biotech 14:315-319; and Stemmer, 1994,Nature 370:389-391. All publications are incorporated herein byreference.

In some embodiments, the clones obtained following mutagenesis treatmentare screened for non-naturally occurring CHMO having a desired enzymeproperty. Measuring CHMO enzyme activity from the expression librariescan be performed using the standard techniques, such as separation ofthe product (e.g., by HPLC) and detection of the product by measuring UVabsorbance of the separated substrate and products and/or by detectionusing tandem mass spectroscopy (e.g., MS/MS). Clones containing apolynucleotide encoding the desired engineered polypeptides are thenisolated, sequenced to identify the nucleotide sequence changes (ifany), and used to express the enzyme in a host cell. Exemplary assaysare provided below in the Examples.

Where the sequence of the polypeptide is known, the polynucleotidesencoding the enzyme can be prepared by standard solid-phase methods,according to known synthetic methods, e.g., the classicalphosphoramidite method described by Beaucage et al., 1981, Tet Lett22:1859-69, or the method described by Matthes et al., 1984, EMBO J.3:801-05. In some embodiments, fragments of up to about 100 bases can beindividually synthesized, then joined (e.g., by enzymatic or chemicallitigation methods, or polymerase mediated methods) to form any desiredcontinuous sequence.

In some embodiments, the present disclosure also provides methods forpreparing or manufacturing the non-naturally occurring polypeptidescapable of converting compound (1a) to compound (2a), or compound (1b)to compound (2b), wherein the methods comprise: (a) culturing a hostcell capable of expressing a polynucleotide encoding the non-naturallyoccurring polypeptide and (b) isolating the polypeptide from the hostcell. The non-naturally occurring polypeptides can be expressed inappropriate cells (as described above), and isolated (or recovered) fromthe host cells and/or the culture medium using any one or more of thewell known techniques used for protein purification, including, amongothers, lysozyme treatment, sonication, filtration, salting-out,ultra-centrifugation, and chromatography. Chromatographic techniques forisolation of the CHMO polypeptide include, among others, reverse phasechromatography high performance liquid chromatography, ion exchangechromatography, gel electrophoresis, and affinity chromatography.

In some embodiments, the non-naturally occurring polypeptide of thedisclosure can be prepared and used in various isolated forms includingbut not limited to crude extracts (e.g., cell-free lysates), powders(e.g., shake-flask powders), lyophilizates, and substantially purepreparations (e.g., DSP powders), as further illustrated in the Examplesbelow.

In some embodiments, the non-naturally occurring polypeptide of thedisclosure can be prepared and used in purified form. Generally,conditions for purifying a particular enzyme will depend, in part, onfactors such as net charge, hydrophobicity, hydrophilicity, molecularweight, molecular shape, etc., and will be apparent to those havingskill in the art. To facilitate purification, it is contemplated that insome embodiments the engineered polypeptides having CHMO activity of thepresent disclosure can be expressed as fusion proteins with purificationtags, such as His-tags having affinity for metals, or antibody tags forbinding to antibodies, e.g., myc epitope tag.

1.4 Methods of Using the Engineered CHMO Polypeptides and CompoundsPrepared Therewith

In some embodiments, the engineered polypeptides having CHMO activitydescribed herein can be used in a method for preparing compound (2a) byconverting compound (1a) to compound (2a) as shown in Scheme 1. Compound(2a) is the active pharmaceutical ingredient, armodafinil, or analogsthereof. The engineered CHMO polypeptides described herein also can beused in a method for preparing compound (2b) by converting compound (1b)to compound (2b), as shown in Scheme 2. Compound (2b) is an intermediatethat can be used in further methods for preparing the activepharmaceutical ingredient of compound (2a), or analogs thereof.Accordingly, in some embodiments the present disclosure also provides aprocess for preparing armodafinil, or an analog thereof, in which theprocess comprises a step of using an engineered polypeptide having CHMOactivity described herein in a method for converting compound (1a) tocompound (2a) or converting compound (1b) to compound (2b).

The methods and processes using the biocatalytic conversions compound(1a) to compound (2a) (as in Scheme 1) or compound (1b) to compound (2b)(as in Scheme 2) can be facilitated by the addition of a NAD⁺ or NADP⁺cofactor recycling system that includes a ketoreductase (KRED) enzymeand secondary substrate for the KRED—e.g., isopropyl alcohol (IPA). Insuch embodiments, the engineered CHMO polypeptide catalyzes theenantioselective addition of a single oxygen atom from molecular oxygeninto the substrate of compound (1a) or compound (1b), followed by thereduction of a second oxygen atom to water. The KRED enzyme recycles thecofactor NAD⁺ to NADH or the cofactor NADP⁺ to NADPH using the secondarysubstrate, IPA (which is converted to acetone), as a reducing agent.

In some embodiments, the disclosure provides a method for preparingcompound (2a) in enantiomeric excess comprising: contacting compound(1a) with an engineered polypeptide of the present disclosure (e.g., asdescribed in Tables 2A, 2B, 2C and elsewhere herein) in the presence ofNADPH or NADH cofactor under suitable reaction conditions. Scheme 1described above illustrates the method of biocatalytic conversion of2-(benzhydrylsulfinyl)acetamide (compound (1a)) to(−)-2-[(R)-(diphenylmethyl)sulfinyl]acetamide (compound (2a)). Suitablereactions conditions for the conversion of compound (1a) to compound(2a) using the engineered CHMO polypeptides of the present disclosureare described in greater detail below and some exemplary suitablereaction conditions also are provided in the Examples.

In brief, the non-naturally occurring CHMO polypeptide of the presentdisclosure, KRED, and NADP⁺ are added to a vial. TEA buffer at basic pHis used to dissolve the enzyme powder. The mixture is stirred gentlyuntil a homogenous solution is obtained. 2-(benzhydrylsulfinyl)acetamide(compound (1a)) is added as a solid powder into the enzyme solutionfollowed by the secondary substrate for the KRED, IPA. The pH of theslurry mixture was re-measured to ensure the reaction pH is 9. Theprogress of the reaction for conversion compound (1a) to compound (2a)(armodafinil) can be monitored by achiral or chiral chromatography,e.g., HPLC methods as described in Examples.

In some embodiments, the disclosure provides methods for preparingcompound (2b) in enantiomeric excess comprising: contacting compound(1b) with an engineered polypeptide of the present disclosure (e.g., asdescribed in Tables 2A, 2B, 2C and elsewhere herein) in the presence ofNADPH or NADH cofactor under suitable reaction conditions. Scheme 2described above illustrates the biocatalytic conversion ofbenzhydryl-thioacetic acid (compound (1b), BHTA) to(R)-2-(benzhydrylsulfinyl)acetic acid (compound (2b), (R)-BHSO,(R)-modafinic acid), which is an intermediate that can be further usedto prepare the amide of compound (2a) (armodafinil). Suitable reactionsconditions for the conversion of compound (1b) to compound (2b) usingthe engineered polypeptides of the present disclosure are described ingreater detail below and some exemplary suitable reaction conditionsalso are provided in the Examples.

The active pharmaceutical ingredient, armodafinil, which is the amide ofcompound (2a), can be prepared from the R-modafinic acid of compound(2b) by esterification and amidation. In brief, the R-modafinic acid ismixed with methanol, and HCl to form a suspension. The methyl ester ofR-modafinic acid then is isolated using standard methods and mixed withmethanol. Subsequently, ammonia is added into the mixture and stirred toform the amide of compound (2a). Crystals of the amide of compound (2a)are precipitated and collected.

Alternatively, R-modafinic acid, is mixed with methanol, and thionylchloride and reacted at room temperature. The methyl ester ofR-modafinic acid is precipitated, filtered and dried. The methyl esterof R-modafinic acid then is mixed with methanol and ammonia hydroxide isadded to the mixture. The mixture is allowed to react thereby formingthe amide of compound (2a). Crystals of the amide of compound (2a) areprecipitated and collected.

In some embodiments, the biocatalytic methods for the conversion of thesubstrate of compound (1a) to compound (2a) or the substrate of compound(1b) to compound (2b) can be carried out wherein a deuterated version ofthe substrate of compound (1a) (i.e., a molecule have the same structureas compound (1a) but with one or more the hydrogen atoms of compound(1a) substituted with a deuterium atom) or the substrate of compound(1b) is used (e.g., US Pat. Publ. No. 20090082461A1). The resultingdeuterated products of compound (2a) or compound (2b) would be producedand could be isolated and further used as described above for thecorresponding non-deuterated product compounds.

As described further below, and illustrated in the Examples, the presentdisclosure contemplates ranges of suitable reaction conditions that canbe used in the methods, including but not limited to ranges of pH,temperature, buffer, solvent system, substrate loading, mixture ofsubstrate compound enantiomers, polypeptide loading, cofactor loading,atmosphere, and reaction time. Further suitable reaction conditions forcarrying out the method for biocatalytic conversion of compound (1a) tocompound (2a) or compound (1b) to compound (2b) using an engineered CHMOpolypeptide described herein can be readily optimized by routineexperimentation that includes, but is not limited to, contacting theengineered CHMO polypeptide and the substrate of compound (1a) orcompound (1b) under experimental reaction conditions of concentration,pH, temperature, solvent conditions, and detecting the production of thecorresponding amide product of compound (2a) or acid product of compound(2b), for example, using the methods described in the Examples providedherein.

As described above, the present disclosure provides a non-naturallyoccurring CHMO polypeptide capable of converting compound (1a) tocompound (2a) in enantiomeric excess and/or compound (1b) to compound(2b) in enantiomeric excess under suitable reaction conditions, whereinthe amino acid sequence of the polypeptide has: (a) sequence identity ofat least 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% to anyone of SEQ ID NO: 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30,32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66,68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100,102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128,130, 132, 134, 136, 138, 140, or 142; and (b) one or more amino aciddifferences relative to SEQ ID NO: 2 selected from: X37E; X277I; X278Aor X278G; X280T or X280Y; X281I; X326R; and X490L or X490Q. In someembodiments, the engineered CHMO can include at least the followingamino acid differences relative SEQ ID NO: 2: X37E; X277I; X278A orX278G; X280T or X280Y; X281I; X326R; X433G; X435A; and X490L or X490Q.In some embodiments, the amino acid sequence of the engineered CHMO caninclude one or more further amino acid differences relative to SEQ IDNO: 2 selected from the following: X3T, X32E, X40G, X42I, X43G, X54V,X62V, X74E, X75M, X79T, X82A, X82I, X84H, X89M, X89N, X99V, X110M,X118V, X123A, X135K, X143G, X143S, X161D, X163L, X163Y, X166A, X166G,X171G, X172A, X172M, X174I, X176S, X182V, X192V, X208T, X216I, X216S,X219V, X227D, X227E, X234D, X243K, X245G, X264Y, X273A, X273C, X273S,X275A, X275N, X275S, X288L, X288V, X290D, X291R, X310E, X310H, X313E,X314L, X314T, X319L, X319T, X322G, X322M, X324K, X325F, X325Y, X329V,X336S, X348A, X362S, X364K, X373V, X382R, X395R, X412L, X426N, X426S,X430R, X438M, X438R, X472I, X473D, X477D, X478L, X484C, X484L, X486E,X489G, X491V, X492K, X492S, X498N, X501D, X503A, X504I, X505K, X512N,X532P, X538E, and X539E.

The improved enzymatic activity of the engineered CHMO polypeptides ofthe present disclosure in the conversion of compound (1a) to compound(2a) in enantiomeric excess and/or compound (1b) to compound (2b) inenantiomeric excess provides for methods wherein higher percentageconversion can be achieved with lower concentrations of the engineeredpolypeptide. The use of lower concentration of the engineeredpolypeptide in a method comprising a conversion of compound (1a) tocompound (2a) or compound (1b) to compound (2b) also reduces the amountof residual protein that may need to be removed in subsequent steps forpurification of the products of compound (2a) or compound (2b). In someembodiments, the methods for preparing compound (2a) or compound (2b) ofthe present disclosure can be carried out wherein the suitable reactionconditions comprise an engineered CHMO polypeptide concentration ofabout 0.1-3.0 g/L, about 0.5-2.75 g/L, about 1.0-2.5 g/L, about 1.5-2.5g/L, about 3 g/L, about 2 g/L, about 1.5 g/L, about 1.0 g/L, about 0.75g/L, or even lower concentration.

The engineered CHMO polypeptides of the present disclosure haveincreased thermal stability relative to the naturally occurring CHMOpolypeptide of SEQ ID NO: 2. This allows the engineered polypeptides tobe used in methods for converting compound (1a) to compound (2a) orcompound (1b) to compound (2b) at higher temperatures which can resultin increased conversion rates and improved substrate solubilitycharacteristics for the reaction. The temperature can be chosen tomaximize the reaction rate at higher temperatures while maintaining theactivity of the enzyme for sufficient duration for efficient conversionof the substrate to the product. Where higher temperatures are used,polypeptides with increased thermostability can be selected to carry outthe process. In certain embodiments, the method can be carried outwherein the suitable reaction conditions comprise a temperature of about10° C. to 50° C., about 20° C. to about 40° C., about 25° C. to about40° C., about 23° C. to about 37° C., about 25° C. to about 35° C.,about 26° C. to about 32° C., about 28° C. to about 30° C. In certainembodiments, the temperature during the enzymatic reaction can bemaintained at ambient (e.g., 25° C.), 27° C., 30° C., 32° C., 35° C.,37° C., 40° C.; or in some embodiments adjusted over a temperatureprofile during the course of the reaction.

In some embodiments of the methods for converting compound (1a) tocompound (2a) or compound (1b) to compound (2b) using the engineeringpolypeptides having CHMO activity of the present disclosure can becarried out wherein the suitable reaction conditions comprise a pH ofabout 7.5 to a pH of about 10.5, a pH of about 8.0 to a pH of about10.0, a pH of about 8.5 to a pH of about 9.5, or a pH of about 8.3 to apH of about 8.7. In some embodiments, the suitable reaction conditionscomprise a pH of about 8.5. During the course of the reaction, the pH ofthe reaction mixture may change. The pH of the reaction mixture may bemaintained at a desired pH or within a desired pH range by the additionof an acid or a base during the course of the reaction. Alternatively,the pH may be controlled by using an aqueous solvent that comprises abuffer.

In some embodiments, the methods for preparing compound (2a) or compound(2b) of the present disclosure can be carried out wherein the suitablereaction conditions comprise a solution comprising an aqueous buffersolution. In some embodiments, the suitable reaction conditions comprisea solution comprising an aqueous buffer solution and an organic solvent,or a co-solvent system. In some embodiments, the aqueous buffer solutionis selected from TEA (e.g., about 0.025 M to about 0.25 M TEA) andpotassium phosphate (e.g., about 0.025 M to about 0.25 M phosphate).Suitable buffers to maintain desired pH ranges are known in the art andinclude, for example, phosphate buffer, triethanolamine buffer, and thelike. Combinations of buffering and acid or base addition may also beused. In some embodiments, the suitable reaction condition comprise TEAat a buffer concentration of from about 50 mM to about 125 mM, or insome embodiments a TEA buffer concentration of about 100 mM. In someembodiments, the suitable reaction condition comprises a phosphatebuffer concentration of about 5 to 50 mM. In certain embodiments, thesolution is a co-solvent system comprising about 70% (v/v) to about 99%(v/v) of an aqueous buffer solution (e.g., about 0.1 M TEA) and about30% to about 1% of an organic solvent solution (e.g., IPA). In someembodiments, the suitable reaction conditions comprise a 0.1 M TEAbuffer, 5% (v/v) IPA, and a pH of about 8.5. In some embodiments, thereaction conditions comprise water as a suitable solvent with no bufferpresent.

In some embodiments, the suitable reaction conditions comprise aco-solvent. Co-solvents can reduce the formation of aggregates which canaffect the rate and scalability of the process. At substrate loading of75 g/L or higher, the use of a co-solvent is desirable. Suitableco-solvents include: MeOH, EtOH, isopropanol (IPA), acetone, toluene,MeCN, methyl tert-butyl ether (MTBE), N-methyl-2-pyrrolidone (NMP),dimethylacetamide (DMAc), dimethylformamide (DMF), propylene glycol,polyethylene glycol (PEG) (e.g., PEG200), tetramethylurea,N-ethylpyrollidinone, tetraglyme,1,3-Dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU), DMIU,hexamethylphosphoramide (HMPA) and dimethylsulfoxide (DMSO).

Choice of co-solvent can be based on evaluating a combination of factorsincluding: compound solubility, compound stability, reaction/processsafety, toxicity, allowable level of solvent in the product (e.g., anAPI product); the effectiveness of the co-solvent in preventingagglomeration of the product, and stability of the monooxygenase to theco-solvent. NMP and PEG200 are particularly suitable co-solvents forreactions with high substrate loading. Accordingly, in some embodimentswith higher substrate loadings (e.g., 100 g/L of compound (1b)), thesuitable reaction conditions comprise about 2%-7.5% (v/v) NMP as aco-solvent. In some embodiments (particularly with higher substrateloadings—e.g., 100 g/L of compound (1b)), the suitable reactionconditions can comprise PEG200 as a co-solvent at a concentration of atleast about 5-15% (v/v), or about 10% (v/v).

The biocatalytic conversion processes described herein (i.e., Scheme 1and Scheme 2) also consumes molecular oxygen as reagent and an oxygenatom is transferred to a sulfide intermediate to yield the sulfoxidefound in the product of compound (2a) and compound (2b). In someembodiments of the methods for converting compound (1a) to compound (2a)or compound (1b) to compound (2b) using the engineered polypeptideshaving CHMO activity of the present disclosure can be carried outwherein the suitable reaction conditions comprise adding dissolved O₂ tothe reaction solution. Dissolved O₂ can be increased by direct spargingof O₂ gas into the reaction solution (e.g., U.S. Pat. No. 6,478,964). Insome embodiments, oxygenation of the reaction solution is done by bubblefree processes. For example, oxygen mass transfer across PTFE membranefor bubble free aeration is described in Schneider et al., 1995, Enzymeand Microbial Technology 17(9):839-847 and European Patent publicationno. EP 0 172 478, which is incorporated herein by reference. DissolvedO₂ also can be increased by increasing the partial pressure of 02 abovethe reaction solution to higher than atmospheric pressure. Accordingly,in some embodiments of the methods the suitable reaction conditionscomprise an 02 partial pressure of at least about 1.25 atm, at leastabout 1.5 atm, at least about 1.75 atm, at least about 2.0 atm, orgreater.

As shown in Scheme 1 and Scheme 2, a cofactor is used in thebiocatalytic reaction converting compound (1a) to compound (2a) orcompound (1b) to compound (2b). The cofactor operates in combinationwith the polypeptides of the disclosure in the process. Suitablecofactors include, but are not limited to, NADP⁺ (nicotinamide adeninedinucleotide phosphate), NADPH (the reduced form of NADP⁺), NAD⁺(nicotinamide adenine dinucleotide) and NADH (the reduced form of NAD⁺).Generally, the reduced form of the cofactor is added to the reactionmixture prior to the start of the reaction. The amount of cofactor usedis the amount needed to drive the biocatalytic reaction of Scheme 1 orScheme 2 to completion (e.g., 95% conversion or greater) and depends onthe substrate loading. In certain embodiments, the method can be carriedout wherein the suitable reaction conditions comprise an NADH or NADPHcofactor concentration of about 0.03-0.5 g/L, about 0.05-0.3 g/L, about0.1-0.2 g/L, about 0.5 g/L, about 0.1 g/L, or about 0.2 g/L.

In some embodiments of the methods for converting compound (1a) tocompound (2a) or compound (1b) to compound (2b) using the engineeredpolypeptides having CHMO activity of the present disclosure can becarried out wherein the suitable reaction conditions comprise using acofactor recycling system to regenerate cofactor NADPH/NADH formNADP⁺/NAD⁺ produced in the reaction. The use of a cofactor recyclingsystem allows the various embodiments of the methods to be carried outwithout adding further cofactor during the reaction. Optionally, thecofactor can replenished by dosing throughout the course of the reactionif no recycling system is used.

In some embodiments of the process, an optional cofactor recyclingsystem can be used to regenerate cofactor NADPH/NADH form NADP+/NAD+produced in the reaction. A cofactor recycling system refers to a set ofreactants that participate in a reaction that reduces the oxidized formof the cofactor (e.g., NADP⁺ to NADPH). Cofactors oxidized by thepolypeptide reduction of the keto substrate are regenerated in reducedform by the cofactor recycling system. Cofactor recycling systemscomprise a stoichiometric reductant that is a source of reducinghydrogen equivalents and is capable of reducing the oxidized form of thecofactor. The cofactor recycling system may further comprise a catalyst,for example an enzyme catalyst that catalyzes the reduction of theoxidized form of the cofactor by the reductant. Various cofactorrecycling systems to regenerate NADH or NADPH from NAD or NADP⁺,respectively, are known in the art and may be used in the methodsdescribed herein.

Suitable exemplary cofactor recycling systems that may be employedinclude, but are not limited to: an alcohol (e.g., isopropanol) and analcohol dehydrogenase or ketoreductase; glucose and glucosedehydrogenase; formate and formate dehydrogenase; glucose-6-phosphateand glucose-6-phosphate dehydrogenase; phosphite and phosphitedehydrogenase, molecular hydrogen and hydrogenase; and the like. Thesesystems may be used in combination with either NADP⁺/NADPH or NAD⁺/NADHas the cofactor. Electrochemical regeneration using hydrogenase may alsobe used as a cofactor recycling system. See, e.g., U.S. Pat. Nos.5,538,867 and 6,495,023, both of which are incorporated herein byreference. Chemical cofactor recycling systems comprising a metalcatalyst and a reducing agent (for example, molecular hydrogen orformate) are also suitable. See, e.g., PCT publication WO 2000/053731,which is incorporated herein by reference.

In some embodiments, the co-factor recycling system can comprise analcohol dehydrogenase or ketoreductase (KRED), which is an NAD⁺ orNADP⁺-dependent enzyme that catalyzes the conversion of an alcohol andNAD⁺ or NADP⁺ to an aldehyde or ketone and NADH or NADPH, respectively.Alcohol dehydrogenases and ketoreductases that are suitable for use ascofactor regenerating systems in the processes described herein includenaturally occurring and non-naturally occurring alcohol dehydrogenasesand ketoreductases. Naturally occurring alcohol dehydrogenases includeknown alcohol dehydrogenase/ketoreductase from, Thermoanerobium brockii,Rhodococcus etythropolis, Lactobacillus kefiri, and Lactobacillusbrevis, and non-naturally occurring alcohol dehydrogenase/ketoreductaseinclude engineered alcohol dehdyrogenase/ketoreductase derivedtherefrom. In some embodiments, non-naturally occurring alcoholdehydrogenase/ketoreductases engineered for thermo- and solventstability can be used. Such engineered alcoholdehydrogenases/ketoreductases are described in the following patentpublications each of which are incorporated by reference herein: US20080318295A1; US 20090093031A1; US 20090155863A1; US 20090162909A1; US20090191605A1; US 20100055751A1; WO/2010/025238A2; WO/2010/025287A2; US20100062499A1; and WO 2008/151324A1. Suitable alcohols to be used with aKRED in the co-factor recycling system include lower secondary alkanolsand aryl-alkyl carbinols. Examples of lower secondary alcohols includeisopropanol (IPA), 2-butanol, 3-methyl-2-butanol, 2-pentanol,3-pentanol, 3,3-dimethyl-2-butanol, and the like. In one embodiment, thesecondary alcohol is isopropanol. Suitable aryl-alkyl carbinols includeunsubstituted and substituted 1-arylethanols.

In some embodiments, the cofactor recycling system can comprise glucosedehydrogenase (GDH), which is a NAD⁺ or NADP⁺-dependent enzyme thatcatalyzes the conversion of D-glucose and NAD⁺ or NADP⁺ to gluconic acidand NADH or NADPH, respectively. Glucose dehydrogenases suitable for usein the practice of the processes described herein include both naturallyoccurring glucose dehydrogenases, as well as non-naturally occurringglucose dehydrogenases. Naturally occurring glucose dehydrogenaseencoding genes have been reported in the literature, e.g., the Bacillussubtilis 61297 GDH gene, B. cereus ATCC 14579 and B. megaterium.Non-naturally occurring glucose dehydrogenases generated using, forexample, mutagenesis, directed evolution, and the like and are providedin PCT publ. no. WO 2005/018579, and US publication Nos. 2005/0095619and 2005/0153417. All of these sequences are incorporated herein byreference.

In some embodiments, the cofactor recycling system can comprise aformate dehydrogenase, which is a NAD⁺ or NADP⁺-dependent enzyme thatcatalyzes the conversion of formate and NAD⁺ or NADP⁺ to carbon dioxideand NADH or NADPH, respectively. Formate dehydrogenases that aresuitable for use as cofactor regenerating systems in the CHMO reactionsdescribed herein include naturally occurring and non-naturally occurringformate dehydrogenases. Suitable formate dehydrogenases are described inPCT publication WO 2005/018579. Formate may be provided in the form of asalt, typically an alkali or ammonium salt (for example, HCO₂Na,KHCO₂NH₄, and the like), in the form of formic acid, typically aqueousformic acid, or mixtures thereof. A base or buffer may be used toprovide the desired pH.

In some embodiments, the co-factor recycling system can comprise aphosphite dehydrogenase, which catalyzes the conversion of phosphite andNAD⁺ or NADP⁺ to a phosphate and NADH or NADPH, respectively. Phosphitedehydrogenases that are suitable for use as cofactor regeneratingsystems in the processes described herein include naturally occurringand non-naturally occurring phosphite dehydrogenases. Naturallyoccurring phosphite dehydrogenases include those from, Pseudomonasstutzeri and Alcaligenes faecalis, and non-naturally occurring phosphitedehydrogenases include engineered phosphite dehydrogenases derivedtherefrom. Phosphite dehydrogenases are described in Johannes et al.,2005, Applied and Environmental Microbiology 71(10):5728-5734; Woodyeret al., 2003, Biochemistry 42 (40):11604-11614; Vrtis et al., 2002,Angewandte Chemie 41(17):3257-3259; Johannes et al., 2006, Biotechnologyand Bioengineering Volume 96(1):18-26; and McLachlan et al., 2008,Biotechnology and Bioengineering 99(2):268-274.

In some embodiments where the cofactor recycling system produces avolatile product from the secondary substrate, such as acetone from IPA.The volatile product can be removed by sparging the reaction solutionwith a non-reactive gas or by applying a vacuum to lower the reactionpressure and removing the volatile present in the gas phase. Anon-reactive gas is any gas that does not react with the reactioncomponents. Various non-reactive gases include nitrogen and noble gases(e.g., inert gases). In some embodiments, the non-reactive gas isnitrogen gas. For example, acetone formed by oxidation of isopropanolcan be removed by sparging with nitrogen gas or applying a vacuum to thereaction solution and removing the acetone from the gas phase by anacetone trap, such as a condenser or other cold trap.

In the embodiments herein, the non-naturally occurring polypeptides forcarrying out the conversion of and any enzymes comprising the optionalcofactor recycling system, may be added to the reaction mixture in theform of the purified enzymes, whole cells transformed with gene(s)encoding the enzymes, and/or cell extracts and/or lysates of such cells.The gene(s) encoding the polypeptides disclosed herein and the optionalcofactor recycling enzymes can be transformed into host cells separatelyor together into the same host cell. Whole cells transformed withgene(s) encoding the engineered CHMO enzyme and/or the optional cofactorregeneration enzymes, or cell extracts and/or lysates thereof, may beemployed in a variety of different forms, including solid (e.g.,lyophilized, spray-dried, and the like) or semisolid (e.g., a crudepaste).

In some embodiments of the methods for converting compound (1a) tocompound (2a) or compound (1b) to compound (2b) using the engineeringCHMO polypeptides of the present disclosure can be carried out whereinthe suitable reaction conditions comprise a substrate loading ofcompound (1a) or compound (1b) of at least about 20 g/L, about 40 g/L,about 50 g/L, about 75 g/L, about 100 g/L, about 200 g/L, about 250 g/L,about 300 g/L, about 400 g/L, or even greater. In certain embodiments,methods for preparing compound (2a) or compound (2b) of the presentdisclosure can be carried out the suitable reaction conditions comprisea substrate loading of compound (1a) or compound (1b) of about 50-100g/L, about 50-200 g/L, about 50-300 g/L, about 50-400 g/L, about 100g/L, about 200 g/L, about 300 g/L or about 400 g/L.

The values for substrate loadings provided herein are based on themolecular weights of the substrates of compound (1a) or compound (1b),however it also contemplated that the equivalent molar amounts ofvarious hydrates and salts of compound (1a) or compound (1b) also can beused in the methods (e.g., a sodium or calcium salt of the acidsubstrate of compound (1b)). Accordingly, in some embodiments of themethods for converting compound (1b) to compound (2b) using anengineered CHMO polypeptide the suitable reaction conditions compriseusing a sodium salt of compound (1b).

The order of addition of reactants is not critical. The reactants may beadded together at the same time to a solvent (e.g., monophasic solvent,biphasic aqueous co-solvent system, and the like), or alternatively,some of the reactants may be added separately, and some together atdifferent time points.

In some embodiments, the methods for preparing compound (2a) or compound(2b) of the present disclosure can be carried out using a combination ofany suitable reaction conditions disclosed above or elsewhere herein,e.g., in the Examples. Accordingly, in some embodiments, the methods ofthe present disclosure can be carried out wherein the suitable reactionconditions comprise: (1) substrate loading of about 25-200 g/L compound(1a) or compound (1b); (2) an engineered CHMO polypeptide concentrationof about 1.5-5.0 g/L; (3) NADPH cofactor concentration of about 0.1-0.2g/L; (4) a KRED concentration of about 0.25-0.75 g/L; (5) a co-solventsolution of an aqueous buffer and about 2.5-7% (v/v) IPA; (6) about pH7.5 to about pH 10.0; and (7) temperature of about 25-45° C. In someembodiments, the suitable reaction conditions can optionally furthercomprise a co-solvent of PEG200 at a concentration of about 5-15% (v/v).In some embodiments, the suitable reaction conditions can optionallyfurther comprise 0.04 vol % of catalase.

In some embodiments, the methods for preparing compound (2a) or compound(2b) of the present disclosure can be carried out wherein the suitablereaction conditions comprise: (1) substrate loading of about 100 g/Lcompound (1a) or compound (1b); (2) engineered CHMO polypeptideconcentration of about 2.5 g/L; (3) NADPH cofactor concentration ofabout 0.1 g/L; (4) a KRED concentration of about 0.5 g/L; (5) aco-solvent solution of an aqueous buffer of 0.1M TEA and about 5% (v/v)IPA; (6) about pH 8.5; and (7) temperature of about 35° C. In someembodiments, the suitable reaction conditions can optionally furthercomprise a co-solvent of PEG200 at a concentration of about 10% (v/v).In some embodiments, the suitable reaction conditions can optionallyfurther comprise 0.04 vol % of catalase.

Generally, in the methods disclosed herein, the biocatalytic reactionwith an engineered CHMO polypeptide under suitable reaction conditionsis allowed to proceed until essentially complete, or near complete,conversion of amide substrate compound (1a) to product compound (2a) orthe conversion of acid substrate compound (1b) to product compound (2b)is obtained. This conversion of substrate to product can be monitoredusing known methods by detecting substrate and/or product. Suitablemethods include gas chromatography, HPLC, and the like, and aredescribed in the Examples.

In some embodiments, the methods for preparing compound (2b) of thepresent disclosure result in at least about 90% conversion of compound(1b) at 100 g/L loading to compound (2b) in 36 h, when carried out underreaction conditions of: engineered CHMO polypeptide concentration ofabout 1.0-3.0 g/L; NADPH cofactor concentration of about 0.1 g/L; a KREDconcentration of 0.5 g/L; a co-solvent system of 0.1 M TEA at pH 8.5, atleast 5% (v/v) IPA, and 10% (v/v) PEG200; and a temperature of 35° C. Insome embodiments, the methods of the present disclosure when carried outunder these suitable reaction conditions (e.g., 100 g/L compound (1b)loading) result in at least about 91%, 92%, 93%, 94%, 95%, 96%, 97%,98%, 99% or greater conversion of the acid substrate compound (1b) toproduct compound (2b) in 24 h.

In some embodiments, the methods for preparing compound (2b) of thepresent disclosure when carried out with 100 g/L compound (1b) loadingresult in an enantiomeric excess of compound (2b) of at least 97%, 98,99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, or 99.9% in24 h.

In some embodiments, the engineered polypeptides of the presentdisclosure can be used in methods for preparing structurally similaranalogs of compounds (2a) or (2b). Such structurally similar analogcompounds can include pharmaceutically active compounds useful for thetreatment of sleep disorders which are described in e.g., U.S. Pat. Nos.4,489,095, 6,6492,396 B2, and 6,670,358 B2, US patent publicationUS2002/0183334 A1, or PCT publication WO 2001/087830 A2, each of whichis hereby incorporated by reference here. Accordingly, structurallysimilar analogs of compound (2b) that can be prepared using theengineered polypeptides, methods, and reaction conditions disclosedherein for use in making of compounds (2a) or (2b), include compounds ofstructural formula (II), which can be prepare from compound ofstructural formula (I) as shown in Scheme 3 below:

The structurally similar analog compounds of structural formula (II)that can be prepared from compounds of formula (I) using the engineeredpolypeptides, methods and conditions described herein can include thefollowing range of structural features:

R¹ is —OH, —OCH₃, —OCH₂CH₃, —NH₂, —NHCH₃, —N(CH₃)₂, —NHOH;

Ar¹ and Ar² are each independently monocyclic or bicyclic aryl orheteroaryl group having 5-6 ring atoms, are each independently,optionally substituted 1 to 3 times with groups R² and/or R³, and areoptionally connected either

-   -   (i) via a group X, wherein X is O, NR, S, CH₂, CH₂CH₂. CH═CH; or    -   (ii) where X is absent and rings Ar¹ and Ar² are connected        directly via a bond; and R² and R³ are independently —H, —F,        —Cl, —Br, —CF₃, —CH₃, —CH₂CH₃, —NH₂, —NHCH₃, or —N(CH₃)₂.

Thus, in some embodiments, the disclosure provides a method forpreparing a compound of structural formula (II) (wherein Ar¹, Ar², R¹,R² and R³ are as defined above) in enantiomeric excess comprising:contacting a compound of structural formula (I) (wherein Ar¹, Ar², R¹,R² and R³ are as defined for formula (II)) with an engineeredpolypeptide of the present disclosure (e.g., as described in Tables 2A,2B, 2C and elsewhere herein) in the presence of NADPH or NADH cofactorunder suitable reaction conditions. Suitable reaction conditions for usein the method of Scheme 3 include those described above for the methodsof preparing compounds (2a) or (2b) (e.g., useful in the methods ofScheme 1 or 2). Specific compounds having structural formula (II) thatcan be made according to this method include the pharmaceutically activecompounds described in U.S. Pat. Nos. 4,489,095, 6,6492,396 B2, and6,670,358 B2, US patent publication US2002/0183334 A1, or PCTpublication WO 2001/087830 A2, each of which is hereby incorporated byreference here.

In the processes herein, the reaction is generally allowed to proceeduntil essentially complete, or near complete. Conversion of substrate toproduct can be monitored using known methods by detecting substrateand/or product. Suitable methods include gas chromatography, HPLC, andthe like.

EXAMPLES

Various features and embodiments of the disclosure are illustrated inthe following representative examples, which are intended to beillustrative, and not limiting.

Example 1: Synthesis, Optimization, and Screening of EngineeredCyclohexanone Monooxygenase (CHMO) Polypeptides

Gene synthesis and optimization: The gene encoding the wild typecyclohexanone monooxygenase (CHMO) from Acinetobacter sp NCIMB9871 (SEQID NO: 2) was designed for expression in E. coli using standard codonoptimization to yield the nucleotide sequence of SEQ ID NO: 1 (standardcodon-optimization methods and software are reviewed in e.g.,“OPTIMIZER:a web server for optimizing the codon usage of DNA sequences,” Puigbò etal., Nucleic Acids Res. 2007 July; 35(Web Server issue): W126-31. Epub2007 Apr. 16). The optimized gene was synthesized using oligonucleotidescomposed of 42 nucleotides and cloned into expression vector pCK110900(which is depicted as FIG. 3 in US Patent Application Publication20060195947, which is hereby incorporated by reference herein) under thecontrol of a lac promoter. The pCK110900 expression vector alsocontained the P15a origin of replication and the chloramphenicolresistance gene. The resulting plasmid was transformed into E. coliW3110 using standard methods. Directed evolution of the codon-optimizedwild-type CHMO gene of SEQ ID NO: 1 was carried out via iterative roundsof variant library generation (e.g., by gene synthesis) followed byscreening for expressed engineered polypeptides with improved properties(including primary HTP assays and secondary SFP assays). The variantpolynucleotides encoding engineered CHMO polypeptides having improvedenzyme properties were sequenced and used to generate new variantlibraries. Variant polynucleotides were cloned into vector pCK110900 forexpression in E. coli W3110 according to the same procedures describedabove for the wild type gene. Engineered CHMO nucleotide and amino acidsequences resulting from this directed evolution are listed in theSequence Listing incorporated by reference herein. The amino acidresidue differences and altered enzyme properties of these engineeredCHMO polypeptides are summarized in Tables 2A, 2B, 2C, above anddescribed further in the Examples below.

Production of shake flask powders (SFP): A shake-flask procedure wasused to generate engineered transaminase polypeptide powders used insecondary screening assays or in the biocatalytic methods of convertingcompound (1a) to compound (2a) or compound (1b) to compound (2b)disclosed herein. Shake flask powder (SFP) include approximately 30%total protein and accordingly provide a more purified preparation of anengineered enzyme as compared to the cell lysate used in HTP assays. Asingle microbial colony of E. coli containing a plasmid encoding anengineered CHMO gene of interest was inoculated into 50 mL Luria Bertanibroth containing 30 μg/ml chloramphenicol and 1% glucose. Cells weregrown overnight (at least 16 hours) in an incubator at 30° C. withshaking at 250 rpm. The culture was diluted into 250 mL Terrific Broth(12 g/L bacto-tryptone, 24 g/L yeast extract, 4 mL/L glycerol, 65 mMpotassium phosphate, pH 7.0, 1 mM MgSO₄) containing 30 μg/mLchloramphenicol, in a 1 L flask to an optical density of 0.2 at 600 nm(OD₆₀₀) and allowed to grow at 30° C. Expression of the CHMO gene wasinduced by addition of isopropyl-β-D-thiogalactoside (IPTG) to a finalconcentration of 1 mM when the OD₆₀₀ of the culture is 0.6 to 0.8, andincubation was then continued overnight (at least 16 hours). Cells wereharvested by centrifugation (5000 rpm, 15 min, 4° C.) and thesupernatant discarded. The cell pellet was resuspended with an equalvolume of cold (4° C.). 25 mM phosphate buffer, pH 9.0, and harvested bycentrifugation as above. The washed cells were resuspended in twovolumes of the cold phosphate buffer and passed through a French Presstwice at 12,000 psi while maintained at 4° C. Cell debris was removed bycentrifugation (9000 rpm, 45 minutes, 4° C.). The clear lysatesupernatant was collected and stored at −20° C. Lyophilization of frozenclear lysate provided a dry shake-flask powder of CHMO polypeptide.Alternatively, the cell pellet (before or after washing) was stored at4° C. or −80° C.

HTP assay of CHMO polypeptides: Primary screening used to guideoptimization was carried out in a ˜200 μL volume in 96-well platehigh-throughput (HTP) assay protocol using cell lysates. The general HTPassay conditions were: 1-100 g/L substrate (i.e., compound (1a) or(1b)), 10-200 μL of clear cell lysate containing the engineered CHMOpolypeptide, 0.05-1.0 g/L NADP cofactor, 1 g/L ketoreductase (KRED)polypeptide for cofactor recycling, 0.025-0.100 M phosphate or TEAbuffer solution containing 3.5%-10% (v/v) IPA (and optionally, 1.5%acetone or 10% PEG200) co-solvent, pH 8-9, 25° C. reaction temperatureand 20 h reaction time (with 200 rpm shaking). The HTP assay conditionswere changed slightly over the different rounds of the directedevolution of the CHMO variant polypeptide disclosed in order to detectthose variants most improved in enzyme properties. Table 4 shows the HTPassay conditions used to perform primary screening of those variantpolypeptides whose improved properties were confirmed by SFP assay assummarized in Tables 2A and 2B. Rounds 1-6 assays used the amidesubstrate of compound (1a) and Rounds 7-16 assays used the acidsubstrate of compound (1b).

TABLE 4 HTP assay conditions SEQ ID Sub- CHMO NADP % NOs strate lysateload IPA T Round assayed (g/L) (μL) (g/L) Buffer (v/v) pH (° C.)  1 2-6 1 200 1 25 10 8.5 25 mM phos- phate  2  8  1  25 0.3 100  5 8 25 mMphos- phate  3 10  1  20 0.3 100  5 8 25 mM phos- phate  4 12-14  1  150.3 100  5 8 25 mM phos- phate  5 16-24  2  10 0.3 100 3.5% 8 25 mMIPA + phos- 1.5% phate ace- tone  6 26-36  2  10 0.3 100 3.5% 8 25 mMIPA + phos- 1.5% phate ace- tone  7 38-46  8 150 0.1 100  5 9 25 mMphos- phate  8 48-80  20 175 0.3 100  5 9 25 mM TEA  9a 82-88  17.5  200.1 100  5 9 25 mM TEA  9b 82-88  31 175 0.1 100  5 9 25 mM TEA 10a 90-  20  15 0.05 100  5 9 25 106 mM TEA 10b 90-   30 120 0.1 100  5 9 25 106mM TEA 11a 108-   20  15 0.05 100  5 9 25 114 mM TEA 11b 108-   35 1200.05 100  5 9 25 114 mM TEA 12a 116-   35  80 0.05 100  5 9 25 118 mMTEA 12b 116-   65 120 0.05 100  5 9 25 118 mM TEA 13 126-   70  30 0.2100  5 9 25 128 mM TEA 14 120-   70  45 0.2 100  5 9 35 124 mM TEA 15a130-   30  10 0.2 100 5% 9 35 132 mM IPA + TEA 10% PEG- 200 15b 130- 100  30 0.2 100 5% 9 35 132 mM IPA + TEA 10% PEG- 200 16a 134-  100  300.2 100 5% 9 35 142 mM IPA + TEA 10% PEG- 200 16b 134-  100  55 0.2 1005% 9 45 142 mM IPA + TEA 10% PEG- 200

At rounds 9-12, additional HTP assays denoted “b” were carried out usinghigher substrate concentrations. The purpose of the “a” assay was toidentify CHMO polypeptides with improved activity (i.e., “rate ofconversion”) and was carried out at a substrate concentration at whichthe enzymatic rate of the parent round polypeptide is highest. Thepurpose of the “b” assay was to identify variants with improvedtolerance towards to increased substrate concentration and was carriedout at a higher substrate concentration at which the parent roundpolypeptide showed low or minimal activity (e.g., less than or equal to5% conversion after 24 hrs).

The general protocol for HTP assays was carried out as follows withadjustments of various reagent concentrations in accordance with assaysconditions at different rounds as described in Table 4. Clear celllysate containing the engineered CHMO polypeptide variant to be screenedwas prepared by shaking cells for 1.5h to 2h at room temperature in a96-well deep well plate containing 500 μL/well of 1.0 g/L Lysozyme, 0.5g/L PMBS, 0.1 M TEA, pH 9. Shaking was followed by centrifugation at4000 rpm and 4° C. for 20 min. A stock KRED-cofactor solution containing1 g/L KRED polypeptide of SEQ ID NO: 144 or 146, and the desiredconcentration of NADP cofactor (0.05-1.0 g/L) was prepared in phosphateor TEA buffer, and adjusted to the desired pH (8-9). A stock substratesolution at the desired concentration also was prepared in the samebuffer and adjusted to the same desired pH. Generally, the assay was runin a total volume of 200-250 μL in a 96-well deep-well plate. To eachwell was added the appropriate volume of the stock KRED-cofactorsolution, the clear cell lysate, and the stock substrate solution, toreach the desired conditions for the particular assay. For example, 75μL of the stock KRED-cofactor solution, 120 μL volume of the clear celllysate, and 90 μL of the stock substrate solution. The reaction wasinitiated by adding 15 μL of isopropyl alcohol. The reaction initiatedby the addition of 15 μL of isopropyl alcohol and then the plate heatsealed and shaken at 200 rpm and 25° C. for ˜20 h. The HTP assayreaction was quenched by addition of 500 μL/well of a solution ofacetonitrile/0.8% trifluoroacetic acid, followed by heat sealing and afurther 200 rpm shaking for 15-20 min at room temperature. The plate wasthen centrifuged at 4000 rpm for 20 min at 25° C. Then 5 μL of thequenched solution was transferred to a shallow well round bottom platecontaining 195 μL acetonitrile which was sealed and shaken for 10 minthen stored at 4° C. until activity and/or enantioselectivity analysisis carried out using HPLC.

SFP assay of CHMO polypeptides: Lysates containing CHMO polypeptidesidentified as hits in the HTP assay (e.g., 1.2-fold improved activityover parent or increased enantioselectivity) were screened in asecondary assay carried out on a 2.00 mL scale using shake-flask powder(SFP) preparations of the engineered CHMO polypeptides. The general SFPassay conditions used to determine activity and enantioselectivity (%e.e.) with the amide substrate of compound (1a) were as follows: 5-10g/L substrate mixture of compound (1a), 3-10 g/L of SFP of theengineered CHMO polypeptide, 0.3-0.5 g/L NADP cofactor, 1 g/L KRED (forcofactor recycling), in a solution of 25 mM-100 mM phosphate buffer,5-10% (v/v) IPA, pH 8.0-8.5, 25° C. reaction temperature and 24 hreaction time (with 400 rpm stirring). The general SFP assay conditionsused to determine activity and enantioselectivity (% e.e.) with the acidsubstrate of compound (1b) were as follows: 10-100 g/L substrate mixtureof compound (1b), 5-10 g/L of SFP of the engineered CHMO polypeptide, 1g/L KRED polypeptide of SEQ ID NO: 144 or 146, 0.2-0.3 g/L NADP, in asolution of 100 mM phosphate buffer or TEA buffer, 5% (v/v) IPA, pH 8.3or pH 9.0, 25° C. reaction temperature and 24 h reaction time (with 400rpm stirring). The specific SFP assay conditions used for the amide andacid substrate SFP assays at the different rounds of the evolution arenoted above in Tables 2A and 2B.

The general SFP assay protocol was as follows. An enzyme solution wasprepared by charging a glass vial equipped with a cross shape stir barwith 8 mg of engineered CHMO polypeptide shake-flask powder (SFP), 4 mgKRED polypeptide of SEQ ID NO: 144 or 146, 0.8 mg NADP cofactor, and 1.8mL 100 mM TEA buffer at 25° C. A substrate solution was prepared bycharging another glass vial with the desired amount amide substrate ofcompound (1a) or acid substrate of compound (1b) (e.g., 120 mg for 30g/L activity assays, or 240 mg for 60 g/L substrate tolerance assays)and 2 mL of 100 mM TEA buffer at 25° C. The pH of the substrate solutionwas adjusted to pH 9 with 10 M NaOH solution. The substrate solutionthen was added to the vial containing the enzyme solution and 0.2 mL IPA(which acts as a substrate for the KRED) was added to start thebiocatalytic reaction. The reaction was stirred at 25° C. and conversionof substrate to product was monitored over time using HPLC (as describedbelow). Enantioselectivity (% e.e.) was determined by chiral HPLCanalysis (as described below) of samples taken at the end of thebiocatalytic reactions.

HPLC sample preparation and activity analysis: An aliquot of 10 μLreaction mixture was diluted into 990 μL of 0.1% TFA in acetonitrile.The sample was centrifuged to remove precipitated enzyme. The sample wasinjected into HPLC for analysis using the instrumental parameters andconditions of Table 5.

TABLE 5 HPLC instrumentation and chromatographic conditions InstrumentAgilent 1200 HPLC system Column Eclipse XDB C18 4.6 × 150 mm, 5 μmMobile Phase A: H₂O + 0.1% TFA B: ACN + 0.1% TFA Time (min) % A % B 0 7030 10 0 100 Column temperature 30° C. Flow rate 1.5 mL/min Injectionvolume 5 μL UV Wavelength 210 nm Runtime (Postime) 10 min (2 min)(R)-BHSO 3.56 min BHTA 5.88 min Linearity 1.999 (R² at 10-70 g/Lproduct)

The % Conversion was calculated from the HPLC trace as follows:

${\%\mspace{14mu}{Conversion}} = {\frac{\left\lbrack {{Peak}\mspace{14mu}{Area}\mspace{14mu}{of}\mspace{14mu}(R)\text{-}{BHSO}} \right\rbrack}{\left\lbrack {{Peak}\mspace{14mu}{Area}\mspace{14mu}{of}\mspace{14mu}(R)\text{-}{BHSO}} \right\rbrack + \left\lbrack {{Peak}\mspace{14mu}{Area}\mspace{14mu}{of}\mspace{14mu}{BHTA}} \right\rbrack} \times 100\%}$

The response factor for (R)-BHSO to BHTA at 210 nm was determined to be1.15:1, based on the relative intensity of signals using a 1:1 molarratio standard solution of (R)-BHSO and BHTA.

Chiral HPLC sample preparation and analysis of productenantioselectivity (% e.e.): 9.8 mg of isolated (R)-BHSO sample wasweighed into a 50 mL volumetric flask and dissolved in 20 mL of EtOH.The mixture was sonicated for 5 min and volume up with EtOH. The samplewas injected into HPLC for analysis using the instrumental parametersand conditions of Table 6.

TABLE 6 HPLC instrumentation and chromatographic conditions InstrumentAgilent HPLC 1200 series Column Chiralpak AD-H 4.6 × 250 mm Mobile Phase(premixed) 90/10 Hexane/IPA + 0.05% TFA Flow Rate 1.50 mL/min DetectionWavelength 225 nm Column Temperature Ambient Injection Volume 5 μL Runtime 15 min Diluent Ethanol LOD 0.45 mg/L (S/N ~3-5) LOQ 1.75 g/L (S/N~8-10)

HTP assay results: Representative results in the primary screening usingthe HTP assay for both the amide substrate (compound (1a)) and the acidsubstrate (compound (2a)) are shown below in Tables 7 and 8.

TABLE 7 HTP Activity amide substrate (relative to SEQ ID NO: SEQ ID NO:2) % ee 1/2 1.0 −52.3 3/4 27.8 87.8 5/6 462 97.9 7/8 692  9/10 117711/12 2095 13/14 2236 15/16 9426 17/18 9845 19/20 14800 21/22 1593023/24 18290 25/26 15460 27/28 39110 29/30 41430 31/32 33700 33/34 3416035/36 40190 37/38 27670 39/40 26120

TABLE 8 HTP Activity Acid Substrate (sodium salt) in substrate toleranceSEQ ID NO: (relative to SEQ NO: 82) 81/82 1 83/84 85/86 87/88 9.6 89/902.0 91/92 9.1 93/94 8.1 95/96 10.8 97/98 7.4  99/100 4.0 101/102 4.0103/104 3.8 105/106 2.4 107/108 7.8 109/110 5.8 111/112 7.6 113/114 7.2115/116 30.8 117/118 36.2 119/120 139 121/122 142 123/124 142 125/126120 127/128 155

Example 2: Preparation of (R)-2-(Benzhydrylsulfinyl)Acetic Acid(Compound (2b)) at 5 g Scale

A 250 mL 3-neck round bottle flask (RBF) was charged sequentially with20 mL of 100 mM TEA buffer solution (pH 10.34), 0.02 g of NADP, 0.1 g ofKRED polypeptide of SEQ ID NO: 144, and 0.5 g of CHMO polypeptide of SEQID NO: 136. The enzyme mixture was stirred gently at 150 rpm until thesolid was dissolved. A 50 mL beaker was charged sequentially with 1.5 gbenzhydrylthioacetic acid (BHTA) (>98%; for preparation see e.g., USpatent publication 200410106829A1 and references therein). 20 mL 100 mMTEA buffer solution (pH 10.34) and 560 μL10 M NaOH (QTëc™). The BHTAmixture was stirred at 25° C. for 15 min to dissolve the solid (pH about9) and this liquid mixture was charged into the RBF containing theenzyme solution. An additional 5.5 mL of 100 mM TEA buffer solution (pH10.34) was used to rinse the beaker and the rinse solution was added tothe RBF. 10 μL of 10 M NaOH was charged into the RBF to adjust the pH ofthe resultant mixture from 8.87 to 9. The mixture was stirred for 1minute at 350 rpm at 25° C. to obtain homogeneity. 2.5 mL of isopropylalcohol (IPA) was added to start the enzymatic reaction.

Another 50 mL beaker was charged sequentially with 3.5 g of BHTA, 36 mLof 100 mM TEA buffer solution containing 5% IPA (pH 10.08), and 1300 μLof 10 M NaOH. The BHTA mixture was stirred at 25° C. for 15 min todissolve the solid and resulting in a substrate solution pH of about 9.The BHTA mixture was transferred to a 50 mL syringe. An additional 9 mLof 100 mM TEA buffer solution containing 5% IPA (pH 10.08) was used torinse the beaker and the rinse solution was added into the syringe. Thevolume of substrate solution in the syringe is 48 mL and theconcentration is 73 g/L.

The mixture in the RBF was stirred at 350 rpm at 25° C. (internaltemperature) for 1 h. BHTA solution (in the syringe) was added to theRBF at a rate of 3 mL/h for 16 hours via a syringe pump. Theconcentration of the substrate and product in the reaction mixture wasperiodically monitored and analyzed by HPLC. After the full conversionto (R)-BHSO (Na salt) at 32 h, the RBF was cooled down to 15° C.(internal temperature) and the pH of the reaction mixture was adjustedfrom pH 8.9 to 3.0 with 4.9 mL of 6M HCl solution. The mixture wasstirred at 250 rpm to precipitate out the (R)-BHSO product as a freesolid.

The white slurry mixture was filtered though a standard G4 sinteredglass funnel under vacuum, dried under air at 25° C. for 1 h andre-dissolved in 50 mL of tetrahydrofuran (Sigma; >99.9% HPLC Grade) at40° C. The mixture was stirred for 20 min until most of the soliddissolved and was filtered through a pad of Celite (3 g) in a standardG4 sintered glass funnel under reduced pressure.

The combined product filtrate was concentrated to 10 mL under vacuum. 20mL of heptane (Sigma; >99.9% HPLC Grade) was added to further enhancethe precipitation of (R)-BHSO. The product was filtered though astandard G4 sintered glass funnel and dried under vacuum, providing 4.9g (92.4% isolated yield) of (R)-BHSO as an off white solid with achemical purity of ˜99.9%, as measured by HPLC.

Example 3: Preparation of (R)-2-(Benzhydrylsulfinyl)Acetic Acid(Compound (2b)) at a 15 g Scale Using a CHMO Variant

This example illustrates a process for preparing the armodafinilintermediate compound, (R)-2-(Benzhydrylsulfinyl)acetic acid (compound(2b)) in enantiomeric excess at a 15 g scale via a biocatalyticconversion using an engineered CHMO polypeptide of the disclosure (e.g.,a polypeptide of SEQ ID NO: 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26,28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62,64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98,100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126,128, 130, 132, 134, 136, 138, 140, or 142.) The procedure describedbelow resulted in 15.9 g (100% yield) of compound (2b) in a single cropas a white solid, and a chemical purity of 99.9% as determined by HPLC.

A. Biocatalytic reaction protocol: A 100 mL beaker equipped with a crossshape stir bar was charged sequentially with: 15 g ofbenzhydrylthioacetic acid (BHTA) substrate (>98%; US patent publication2004/0106829A1 and references therein), 77 mL of 100 mM TEA buffersolution (pH 10.3), 5.56 mL, of 10 M NaOH, and 15 mL of PEG 200 (SigmaReagent Grade). This substrate mixture was stirred at 35° C. for 20 minuntil all of the solid dissolved, resulting in a pH of about 8.3. A 300mL Parr reactor vessel was fitted with a turbine impeller, an oxygen gasinlet/outlet and a dosing needle inlet. The reaction vessel at 35° C.was charged sequentially with: 30 mL of 100 mM TEA buffer solution (pH10.3), 0.03 g of NADP, 0.15 g of KRED polypeptide of SEQ ID NO: 144, and0.3 g of engineered CHMO polypeptide of SEQ ID NO: 136. This enzymemixture was stirred gently at 150 rpm until all the solid powderdissolved, affording a homogenous yellow solution. The substratesolution mixture was charged into the Parr reactor vessel containing theenzyme solution. The pH of the resultant mixture was 8.54. The mixturewas stirred for 1 minute at 350 rpm at 35° C. to obtain homogeneity. 7.5mL of IPA (Sigma; >99.9% HPLC Grade) was added to initiate the KREDcofactor recycling reaction and thereby start the CHMO enzymaticreaction. The final pH was found to be 8.50. The reaction course wasfollowed periodically by taking samples from the reaction mixture,quenching, and analyzing as described in Method 1. For the purposes oftracking the process, t=0 was set at the time at which IPA was added.The in-process reaction profile was determined using achiral HPLCanalysis as described above in Example 1. The in-process sample analysesare summarized in Table 9 below.

TABLE 9 Reaction Profile Time (h) % Conversion 0 0 3 20.5 6 36.5 26 94.530 97.6 33 98.8 36 99.4 48 99.9

A % conversion of >99% within 36 hours can be estimated from the kineticprofile of the reaction. The reaction mixture 48 hours after start wastaken for product work-up and isolation as described below.

B. Reaction work-up protocol: The reaction vessel was cooled to 15° C.(internal temperature) and the pH of the reaction mixture was adjustedfrom pH 8.25 to 3.0 by adding 11.1 mL of 6 M HCl solution withcontinuous stirring at 250 rpm to precipitate out the(R)-2-(benzhydrylsulfinyl)acetic acid product as a free solid. The whiteslurry mixture was filtered though a standard G4 sintered glass funnelunder vacuum and the reaction vessel was twice rinsed with 15 mL of colddeionized water at 5° C. (acidified with HCl to pH 3) and the filtercake was then washed with the deionized water rinse. HPLC analysis ofthe mother liquor indicated that 0.5% of(R)-2-(benzhydrylsulfinyl)acetic acid product was still present. Theproduct was dried under vacuum to afford 15.9 g (100% isolated yield,99.85% e.e.) of (R)-2-(benzhydrylsulfinyl)acetic acid as a white solid.

Example 4: Process I for the Preparation of Armodafinil from(R)-2-(Benzhydrylsulfinyl)Acetic Acid (Compound (2b)) (Use of 32% HClTreatment)

In the first step, a 50 mL flask was charged with R-modafinic acid (5g), methanol (5 mL) and HCl 32% (0.1 mL) to form a suspension. Thesuspension was stirred at ambient temperature for 24 hours to obtain acrystalline precipitate, which were collected by filtration and analyzedto be the corresponding methyl ester. In the second step, the wetisolated methyl ester was mixed with methanol. Subsequently, ammonia(gas) was bubbled into the mixture for 30 min and the mixture wasstirred for 12 hours. Precipitated crystals were collected andidentified as armodafinil.

Example 5: Process II for the Preparation of Armodafinil from(R)-2-(Benzhydrylsulfinyl)Acetic Acid (R-Modafinic Acid) (Treatment withThienyl Chloride)

A 100 mL flask was charged with modafinic acid (3.0 g) and methanol (50mL) and cooled to 0° C. Thionyl chloride (0.8 g, 0.5 eq.) was added dropwise. The reaction mixture was maintained at room temperature for atleast 3 hours, and then cooled to 0° C. The methyl ester of modafinicacid was precipitated, filtered and dried. The methyl ester of modafinicacid was mixed with methanol (5 mL/g) and ammonia hydroxide (15 mL/g)was added to the mixture. The mixture was stirred overnight and theprecipitated crystals were collected and determined to be armodafinil.

Example 6: Biocatalytic Preparation of Armodafinil (Compound (2a)) from2-(benzhydrylsulfinyl)acetamide (Compound (1a))

40 mg of the engineered CHMO polypeptide SFP of SEQ ID NO: 38, 4 mg ofKRED enzyme of SEQ ID NO: 146, and 0.8 mg of NADP were added to a 20 mLvial equipped with a cross shaped stirring bar. 3.8 mL of 100 mM TEAbuffer at pH 9 was used to dissolve the enzyme powder. The mixture wasstirred gently until a homogenous yellow solution was obtained. 80 mg of2-(benzhydrylsulfinyl)acetamide (compound (1a)) was added as a solidpowder into the enzyme solution followed by 0.2 mL of IPA. The pH of theslurry mixture was re-measured to ensure the reaction pH is 9. Theprogress of the reaction was monitored by HPLC.

The invention, and the manner and process of making and using it, arenow described in such full, clear, concise and exact terms as to enableany person skilled in the art to which it pertains, to make and use thesame. It is to be understood that the foregoing describes preferredembodiments of the present disclosure and that modifications can be madetherein without departing from the scope of the present invention as setforth in the claims. To particularly point out and distinctly claim thesubject matter regarded as the invention, the following claims concludethis specification.

What is claimed is:
 1. A non-naturally occurring polynucleotide encodinga non-naturally occurring polypeptide having cyclohexanone monooxygenase(CHMO) activity wherein the amino acid sequence of the polypeptide hasat least 90% sequence identity to SEQ ID NO: 2, and one or more aminoacid substitutions at one or more positions corresponding to positionsin SEQ ID NO: 2, selected from the group consisting of 75, 79, 82, 99,110, 166, 172, 208, 216, 273, 324, 364, 395, 412, 491, 503, and
 504. 2.The non-naturally occurring polynucleotide of claim 1, wherein saidnon-naturally occurring polypeptide is further capable of converting theacid substrate compound (1b) to compound (2b) (R-enantiomer) or itsopposite enantiomer compound (S-enantiomer)

with at least 2-fold improved activity relative to the wild-typepolypeptide of SEQ ID NO:
 2. 3. The non-naturally occurringpolynucleotide of claim 1, wherein said non-naturally occurringpolypeptide further comprises one or more amino acid substitutionsrelative to SEQ ID NO: 2, wherein the polypeptide comprises an alanine,glutamic acid, glycine, isoleucine, lysine, proline, serine, threonine,or valine at a position corresponding to position 246 of SEQ ID NO: 2.4. The non-naturally occurring polynucleotide of claim 1, wherein saidnon-naturally occurring polypeptide is further capable of converting theacid substrate of compound (1b) to the R-enantiomer compound (2b)

in at least 50% enantiomeric excess.
 5. The non-naturally occurringpolynucleotide of claim 1, wherein said non-naturally occurringpolypeptide further comprises one or more amino acid differencesrelative to SEQ ID NO: 2, wherein said polypeptide further comprises oneor more substitutions corresponding to substitutions in SEQ ID NO: 2selected from the group consisting of a glycine at position 143, aglycine at position 278, an arginine at position 326, and a lysine atposition
 490. 6. The non-naturally occurring polynucleotide of claim 1,wherein said non-naturally occurring polypeptide further comprises anisoleucine at a position corresponding to position 277 of SEQ ID NO: 2,an alanine or glycine at a position corresponding to position 278 of SEQID NO: 2, a threonine or tyrosine at a position corresponding toposition 280 of SEQ ID NO: 2, an isoleucine at a position correspondingto position 281 of SEQ ID NO: 2, an arginine at a position correspondingto position 326 of SEQ ID NO: 2, and a lysine or glutamine at a positioncorresponding to position 490 of SEQ ID NO:
 2. 7. The non-naturallyoccurring polynucleotide of claim 1, wherein said non-naturallyoccurring polypeptide is further capable of converting compound (1a) tocompound (2a)

in at least 75% enantiomeric excess under suitable reaction conditions.8. The non-naturally occurring polynucleotide of claim 1, wherein saidnon-naturally occurring polypeptide is further capable of convertingcompound (1a) to compound (2a)

with an activity increased at least 2-fold relative to the activity ofthe polypeptide of SEQ ID NO: 2, under suitable reaction conditions. 9.The non-naturally occurring polynucleotide of claim 6, wherein saidnon-naturally occurring polypeptide sequence further comprises acombination of amino acid substitutions relative to SEQ ID NO: 2,selected from the following group consisting of: (a) the amino acid atposition 3 is threonine, the amino acid at position 43 is glycine, theamino acid at position 75 is methionine, the amino acid at position 143is glycine, the amino acid at position 166 is alanine, the amino acid atposition 280 is tyrosine, the amino acid at position 395 is arginine,the amino acid at position 412 is leucine, the amino acid at position426 is serine, the amino acid at position 432 is serine, the amino acidat position 433 is glycine, the amino acid at position 435 is alanine,the amino acid at position 491 is valine, the amino acid at position 503is alanine, the amino acid at position 504 is isoleucine, the amino acidat position 512 is asparagine, and the amino acid at position 532 isproline; (b) the amino acid at position 3 is threonine, the amino acidat position 43 is glycine, the amino acid at position 75 is methionine,the amino acid at position 99 is valine, the amino acid at position 143is glycine, the amino acid at position 161 is aspartic acid, the aminoacid at position 166 is alanine, the amino acid at position 174 isisoleucine, the amino acid at position 273 is serine, the amino acid atposition 280 is tyrosine, the amino acid at position 324 is lysine, theamino acid at position 395 is arginine, the amino acid at position 412is leucine, the amino acid at position 426 is serine, the amino acid atposition 432 is serine, the amino acid at position 433 is glycine, theamino acid at position 435 is alanine, the amino acid at position 491 isvaline, the amino acid at position 503 is alanine, the amino acid atposition 504 is isoleucine, the amino acid at position 512 isasparagine, and the amino acid at position 532 is proline; (c) the aminoacid at position 3 is threonine, the amino acid at position 43 isglycine, the amino acid at position 75 is methionine, the amino acid atposition 79 is threonine, the amino acid at position 82 is alanine, theamino acid at position 99 is valine, the amino acid at position 110 ismethionine, the amino acid at position 143 is glycine, the amino acid atposition 161 is aspartic acid, the amino acid at position 166 isalanine, the amino acid at position 174 is isoleucine, the amino acid atposition 208 is threonine, the amino acid at position 273 is serine, theamino acid at position 280 is tyrosine, the amino acid at position 324is lysine, the amino acid at position 395 is arginine, the amino acid atposition 412 is leucine, the amino acid at position 426 is serine, theamino acid at position 432 is serine, the amino acid at position 433 isglycine, the amino acid at position 435 is alanine, the amino acid atposition 491 is valine, the amino acid at position 503 is alanine, theamino acid at position 504 is isoleucine, the amino acid at position 505is lysine, the amino acid at position 512 is asparagine, and the aminoacid at position 532 is proline; (d) the amino acid at position 3 isthreonine, the amino acid at position 43 is glycine, the amino acid atposition 75 is methionine, the amino acid at position 79 is threonine,the amino acid at position 82 is alanine, the amino acid at position 99is valine, the amino acid at position 110 is methionine, the amino acidat position 143 is glycine, the amino acid at position 161 is asparticacid, the amino acid at position 166 is alanine, the amino acid atposition 174 is isoleucine, the amino acid at position 208 is threonine,the amino acid at position 273 is serine, the amino acid at position 280is tyrosine, the amino acid at position 324 is lysine, the amino acid atposition 395 is arginine, the amino acid at position 412 is leucine, theamino acid at position 426 is serine, the amino acid at position 432 isserine, the amino acid at position 433 is glycine, the amino acid atposition 435 is alanine, the amino acid at position 472 is isoleucine,the amino acid at position 486 is glutamic acid, the amino acid atposition 491 is valine, the amino acid at position 503 is alanine, theamino acid at position 504 is isoleucine, the amino acid at position 505is lysine, the amino acid at position 512 is asparagine, and the aminoacid at position 532 is proline; (e) the amino acid at position 3 isthreonine, the amino acid at position 43 is glycine, the amino acid atposition 75 is methionine, the amino acid at position 79 is threonine,the amino acid at position 82 is alanine, the amino acid at position 99is valine, the amino acid at position 110 is methionine, the amino acidat position 143 is glycine, the amino acid at position 161 is asparticacid, the amino acid at position 166 is alanine, the amino acid atposition 174 is isoleucine, the amino acid at position 208 is threonine,the amino acid at position 234 is aspartic acid, the amino acid atposition 273 is serine, the amino acid at position 280 is tyrosine, theamino acid at position 324 is lysine, the amino acid at position 395 isarginine, the amino acid at position 412 is leucine, the amino acid atposition 426 is serine, the amino acid at position 432 is serine, theamino acid at position 433 is glycine, the amino acid at position 435 isalanine, the amino acid at position 438 is methionine, the amino acid atposition 472 is isoleucine, the amino acid at position 486 is glutamicacid, the amino acid at position 490 is glutamine, the amino acid atposition 491 is valine, the amino acid at position 503 is alanine, theamino acid at position 504 is isoleucine, the amino acid at position 505is lysine, the amino acid at position 512 is asparagine, and the aminoacid at position 532 is proline; (f) the amino acid at position 3 isthreonine, the amino acid at position 43 is glycine, the amino acid atposition 75 is methionine, the amino acid at position 79 is threonine,the amino acid at position 82 is alanine, the amino acid at position 99is valine, the amino acid at position 110 is methionine, the amino acidat position 143 is glycine, the amino acid at position 161 is asparticacid, the amino acid at position 166 is alanine, the amino acid atposition 174 is isoleucine, the amino acid at position 208 is threonine,the amino acid at position 273 is serine, the amino acid at position 280is tyrosine, the amino acid at position 324 is lysine, the amino acid atposition 395 is arginine, the amino acid at position 412 is leucine, theamino acid at position 426 is serine, the amino acid at position 432 isserine, the amino acid at position 433 is glycine, the amino acid atposition 435 is alanine, the amino acid at position 438 is methionine,the amino acid at position 472 is isoleucine, the amino acid at position484 is cysteine, the amino acid at position 486 is glutamic acid, theamino acid at position 490 is glutamine, the amino acid at position 491is valine, the amino acid at position 503 is alanine, the amino acid atposition 504 is isoleucine, the amino acid at position 505 is lysine,the amino acid at position 512 is asparagine, and the amino acid atposition 532 is proline; (g) the amino acid at position 3 is threonine,the amino acid at position 43 is glycine, the amino acid at position 75is methionine, the amino acid at position 79 is threonine, the aminoacid at position 82 is alanine, the amino acid at position 99 is valine,the amino acid at position 110 is methionine, the amino acid at position143 is glycine, the amino acid at position 161 is aspartic acid, theamino acid at position 166 is alanine, the amino acid at position 172 isalanine, the amino acid at position 174 is isoleucine, the amino acid atposition 208 is threonine, the amino acid at position 243 is lysine, theamino acid at position 245 is glycine, the amino acid at position 273 isserine, the amino acid at position 280 is tyrosine, the amino acid atposition 319 is threonine, the amino acid at position 324 is lysine, theamino acid at position 325 is tyrosine, the amino acid at position 395is arginine, the amino acid at position 412 is leucine, the amino acidat position 426 is serine, the amino acid at position 432 is serine, theamino acid at position 433 is glycine, the amino acid at position 435 isalanine, the amino acid at position 438 is methionine, the amino acid atposition 472 is isoleucine, the amino acid at position 484 is cysteine,the amino acid at position 486 is glutamic acid, the amino acid atposition 490 is glutamine, the amino acid at position 491 is valine, theamino acid at position 492 is lysine, the amino acid at position 501 isaspartic acid, the amino acid at position 503 is alanine, the amino acidat position 504 is isoleucine, the amino acid at position 505 is lysine,the amino acid at position 512 is asparagine, and the amino acid atposition 532 is proline; (h) the amino acid at position 3 is threonine,the amino acid at position 43 is glycine, the amino acid at position 62is valine, the amino acid at position 75 is methionine, the amino acidat position 79 is threonine, the amino acid at position 82 is alanine,the amino acid at position 99 is valine, the amino acid at position 110is methionine, the amino acid at position 143 is glycine, the amino acidat position 161 is aspartic acid, the amino acid at position 166 isalanine, the amino acid at position 174 is isoleucine, the amino acid atposition 208 is threonine, the amino acid at position 273 is serine, theamino acid at position 275 is serine, the amino acid at position 280 istyrosine, the amino acid at position 324 is lysine, the amino acid atposition 329 is valine, the amino acid at position 395 is arginine, theamino acid at position 412 is leucine, the amino acid at position 426 isserine, the amino acid at position 432 is serine, the amino acid atposition 433 is glycine, the amino acid at position 435 is alanine, theamino acid at position 438 is methionine, the amino acid at position 472is isoleucine, the amino acid at position 484 is cysteine, the aminoacid at position 486 is glutamic acid, the amino acid at position 490 isglutamine, the amino acid at position 491 is valine, the amino acid atposition 503 is alanine, the amino acid at position 504 is isoleucine,the amino acid at position 505 is lysine, the amino acid at position 512is asparagine, and the amino acid at position 532 is proline; (i) theamino acid at position 3 is threonine, the amino acid at position 43 isglycine, the amino acid at position 75 is methionine, the amino acid atposition 79 is threonine, the amino acid at position 82 is alanine, theamino acid at position 99 is valine, the amino acid at position 110 ismethionine, the amino acid at position 118 is valine, the amino acid atposition 143 is glycine, the amino acid at position 161 is asparticacid, the amino acid at position 166 is alanine, the amino acid atposition 172 is alanine, the amino acid at position 174 is isoleucine,the amino acid at position 208 is threonine, the amino acid at position216 is isoleucine, the amino acid at position 264 is tyrosine, the aminoacid at position 273 is serine, the amino acid at position 280 istyrosine, the amino acid at position 291 is arginine, the amino acid atposition 310 is histidine, the amino acid at position 319 is threonine,the amino acid at position 324 is lysine, the amino acid at position 325is tyrosine, the amino acid at position 395 is arginine, the amino acidat position 412 is leucine, the amino acid at position 426 is serine,the amino acid at position 432 is serine, the amino acid at position 433is glycine, the amino acid at position 435 is alanine, the amino acid atposition 438 is methionine, the amino acid at position 472 isisoleucine, the amino acid at position 484 is cysteine, the amino acidat position 486 is glutamic acid, the amino acid at position 490 isglutamine, the amino acid at position 491 is valine, the amino acid atposition 492 is lysine, the amino acid at position 501 is aspartic acid,the amino acid at position 503 is alanine, the amino acid at position504 is isoleucine, the amino acid at position 505 is lysine, the aminoacid at position 512 is asparagine, and the amino acid at position 532is proline; (j) the amino acid at position 3 is threonine, the aminoacid at position 43 is glycine, the amino acid at position 75 ismethionine, the amino acid at position 79 is threonine, the amino acidat position 82 is alanine, the amino acid at position 89 is asparagine,the amino acid at position 99 is valine, the amino acid at position 110is methionine, the amino acid at position 118 is valine, the amino acidat position 143 is serine, the amino acid at position 161 is asparticacid, the amino acid at position 166 is alanine, the amino acid atposition 172 is alanine, the amino acid at position 174 is isoleucine,the amino acid at position 208 is threonine, the amino acid at position216 is isoleucine, the amino acid at position 219 is valine, the aminoacid at position 264 is tyrosine, the amino acid at position 273 isserine, the amino acid at position 275 is alanine, the amino acid atposition 280 is tyrosine, the amino acid at position 291 is arginine,the amino acid at position 310 is histidine, the amino acid at position319 is threonine, the amino acid at position 324 is lysine, the aminoacid at position 325 is tyrosine, the amino acid at position 362 isserine, the amino acid at position 395 is arginine, the amino acid atposition 412 is leucine, the amino acid at position 426 is serine, theamino acid at position 432 is serine, the amino acid at position 433 isglycine, the amino acid at position 435 is alanine, the amino acid atposition 438 is methionine, the amino acid at position 472 isisoleucine, the amino acid at position 477 is aspartic acid, the aminoacid at position 484 is cysteine, the amino acid at position 486 isglutamic acid, the amino acid at position 490 is glutamine, the aminoacid at position 491 is valine, the amino acid at position 492 islysine, the amino acid at position 501 is aspartic acid, the amino acidat position 503 is alanine, the amino acid at position 504 isisoleucine, the amino acid at position 505 is lysine, the amino acid atposition 512 is asparagine, and the amino acid at position 532 isproline; and (k) the amino acid at position 3 is threonine, the aminoacid at position 43 is glycine, the amino acid at position 75 ismethionine, the amino acid at position 79 is threonine, the amino acidat position 82 is alanine, the amino acid at position 84 is histidine,the amino acid at position 89 is asparagine, the amino acid at position99 is valine, the amino acid at position 110 is methionine, the aminoacid at position 118 is valine, the amino acid at position 143 isserine, the amino acid at position 161 is aspartic acid, the amino acidat position 166 is alanine, the amino acid at position 172 is alanine,the amino acid at position 174 is isoleucine, the amino acid at position208 is threonine, the amino acid at position 216 is isoleucine, theamino acid at position 219 is valine, the amino acid at position 264 istyrosine, the amino acid at position 273 is serine, the amino acid atposition 275 is alanine, the amino acid at position 278 is alanine, theamino acid at position 280 is tyrosine, the amino acid at position 291is arginine, the amino acid at position 310 is histidine, the amino acidat position 319 is threonine, the amino acid at position 324 is lysine,the amino acid at position 325 is tyrosine, the amino acid at position362 is serine, the amino acid at position 395 is arginine, the aminoacid at position 412 is leucine, the amino acid at position 426 isserine, the amino acid at position 432 is serine, the amino acid atposition 433 is glycine, the amino acid at position 435 is alanine, theamino acid at position 438 is methionine, the amino acid at position 472is isoleucine, the amino acid at position 473 is aspartic acid, theamino acid at position 484 is leucine, the amino acid at position 486 isglutamic acid, the amino acid at position 490 is glutamine, the aminoacid at position 491 is valine, the amino acid at position 492 islysine, the amino acid at position 498 is asparagine, the amino acid atposition 501 is aspartic acid, the amino acid at position 503 isalanine, the amino acid at position 504 is isoleucine, the amino acid atposition 505 is lysine, the amino acid at position 512 is asparagine,and the amino acid at position 532 is proline.
 10. The non-naturallyoccurring polynucleotide of claim 1, wherein said non-naturallyoccurring polypeptide is further capable of converting compound (1b) tocompound (2b)

in enantiomeric excess under suitable reaction conditions.
 11. Thenon-naturally occurring polynucleotide of claim 6, wherein saidnon-naturally occurring polypeptide is further capable of convertingcompound (1b) to compound (2b)

in at least 75% enantiomeric excess under suitable reaction conditions.12. The non-naturally occurring polynucleotide of claim 6, wherein saidnon-naturally occurring polypeptide is further capable of convertingcompound (1b) to compound (2b)

with an activity increased at least 2-fold relative to the activity ofthe polypeptide of SEQ ID NO: 2, under suitable reaction conditions. 13.The non-naturally occurring polynucleotide of claim 10, wherein saidnon-naturally occurring polypeptide is capable of at least 90% orgreater conversion of compound (1b) to compound (2b) in 24 h with asubstrate loading of about 50 g/L.
 14. The non-naturally occurringpolynucleotide of claim 1, wherein said non-naturally occurringpolypeptide further comprises at least one amino acid substitution atpositions corresponding to positions in SEQ ID NO: 2, selected from 32,40, 42, 54, 62, 74, 123, 135, 163, 171, 176, 182, 192, 227, 264, 288,290, 313, 314, 322, 329, 336, 348, 373, 382, 430, 472, 478, 489, 538,and
 539. 15. The non-naturally occurring polynucleotide of claim 14,wherein said non-naturally occurring polypeptide comprises one or moresubstitutions corresponding to substitutions in SEQ ID NO:2, selectedfrom the group consisting of: the amino acid at position 32 is glutamicacid, the amino acid at position 40 is glycine, the amino acid atposition 42 is isoleucine, the amino acid at position 54 is valine, theamino acid at position 62 is valine, the amino acid at position 74 isglutamic acid, the amino acid at position 123 is alanine, the amino acidat position 135 is lysine, the amino acid at position 163 is leucine ortyrosine, the amino acid at position 171 is glycine, the amino acid atposition 176 is serine, the amino acid at position 182 is valine, theamino acid at position 192 is valine, the amino acid at position 227 isaspartic acid or glutamic acid, the amino acid at position 264 istyrosine, the amino acid at position 288 is leucine or valine, the aminoacid at position 290 is aspartic acid, the amino acid at position 313 isglutamic acid, the amino acid at position 314 is leucine or threonine,the amino acid at position 322 is glycine or methionine, the amino acidat position 329 is valine, the amino acid at position 336 is serine, theamino acid at position 348 is alanine, the amino acid at position 373 isvaline, the amino acid at position 382 is arginine, the amino acid atposition 430 is arginine, the amino acid at position 489 is glycine, theamino acid at position 538 is glutamic acid, and the amino acid atposition 539 is glutamic acid.
 16. The non-naturally occurringpolynucleotide of claim 1, wherein said polynucleotide comprises asequence having at least 90% identity to SEQ ID NO:
 1. 17. An expressionvector comprising the non-naturally occurring polynucleotide of claim 1.18. A host cell comprising the expression vector of claim 17.